# Tabby's star (KIC 8462852)

> KIC 8462852, an ordinary-looking F-type star in Cygnus, dimmed by up to about 20 per cent at irregular intervals in Kepler data from 2009 to 2013, and…

Source: https://mysteriesdept.com/mysteries/tabbys-star  
Publisher: Mysteries Department  
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Updated: 2026-10-30T21:53:46+00:00  

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**MYS** 0D8E71V402ZV·Mystery · signal

# Tabby's star (KIC 8462852)

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Tabby's star (KIC 8462852)

![Star KIC 8462852 in infrared (2MASS survey) and ultraviolet (GALEX).](https://mysteriesdept.com/media/folio/tabbys-star-lead)

Infrared: IPAC/NASA Ultraviolet: STScI · Public domain

Star

KIC 8462852 (TIC 185336364), F3 main-sequence star in Cygnus; also called Boyajian's star⁠[[1]]

Position

RA 301.5644°, Dec +44.4569° (J2000)⁠[[42]]

Dips

Irregular, aperiodic dips of up to about 20 per cent in Kepler data, 2009–2013⁠[[1]]

Found by

Planet Hunters citizen scientists, reported 2015⁠[[1]]

Fade in Kepler

About 3 per cent over four years, 0.9 per cent of it gradual and more than 2 per cent in about 200 days⁠[[4]]

Colour of dips

Deeper in blue than red; consistent with dust grains much smaller than 1 micron⁠[[7]]

Companion

A bound M-dwarf companion at about 880 au projected separation⁠[[40]]

Century fade

+0.166 ± 0.020 mag per century in DASCH DR7, the steepest of 50 matched stars but only about 2 sigma above them; flat before 1953⁠[[31]]

Latest

A 1.1 per cent symmetric dip on 3 September 2019 in TESS Sector 15, modelled as a giant-planet transit; no dips to 0.5 per cent in the 2024 sectors⁠[[14]]

Status

Partly explained

Questions

0 of 8 answered

People [**Bradley E. Schaefer** Astronomer, Louisiana State University; measured the century-long fade](https://mysteriesdept.com/mysteries/tabbys-star/people/FIG0D8E72JJ4Y89/bradley-e-schaefer)[**Jason T. Wright** Penn State astronomer; set out the family of explanations, including megastructures](https://mysteriesdept.com/mysteries/tabbys-star/people/FIG0D8E73A056EW/jason-t-wright)[**Michael Hippke** Lead author of the critique of plate photometry](https://mysteriesdept.com/mysteries/tabbys-star/people/FIG0D8E72TC7JNJ/michael-hippke)[**Tabetha S. Boyajian** Astronomer, Louisiana State University; led the discovery paper and the 2017 campaign](https://mysteriesdept.com/mysteries/tabbys-star/people/FIG0D8E72AR69B6/tabetha-s-boyajian)[**Benjamin T. Montet** Measured the Kepler-era fade with Joshua Simon](https://mysteriesdept.com/mysteries/tabbys-star/people/FIG0D8E73267WND/benjamin-t-montet)

Catalog key**MYS** 0D8E71V402ZV

KIC 8462852 is a star a little hotter than the Sun in the constellation Cygnus, one of the stars that NASA's Kepler telescope watched continuously from 2009 to 2013 to find planets by the small, regular dips they cause when they cross a star⁠[[1]]. In 2015 volunteers in the Planet Hunters project, who inspect Kepler light curves by eye, flagged it for something else: dips that were deep, irregular and not periodic. Some removed a few tenths of a per cent of the light; others removed up to about 20 per cent, and their shapes were lopsided and complex. A team led by Tabetha Boyajian ruled out instrumental causes, found the star itself unremarkable, found no excess infrared light from warm dust, and concluded that the most consistent of the explanations it could test was a family of comet or planetesimal fragments passing in front of the star⁠[[1]].

Two further findings made the case harder. In 2016 Bradley Schaefer measured the star on Harvard photographic plates from 1890 to 1989 and reported a fade of about 0.16 magnitudes per century, which would need far more dust than the dips⁠[[2]]; other analysts showed that plate photometry drifts by similar amounts and that the century fade could not be considered significant⁠[[3]]. Kepler's own full-frame images then showed a fade of about 3 per cent over the four years of the mission, part of it in a steep 200-day drop that no comparison star matched⁠[[4]]. With the fade added, a cloud of comets looked less adequate, and the possibility that the star is surrounded by artificial structures, which a Penn State group had set out as a testable hypothesis, was among the readings that had to be tested⁠[[5]]⁠[[6]].

The deciding observations came in 2017, when the star began dipping again under a crowd-funded monitoring campaign. Four dips of 1 to 2.5 per cent were caught in several colours at once: each was deeper in blue light than red, with no change in the stellar spectrum, which is what fine dust does and what an opaque object of any kind does not⁠[[7]]⁠[[8]]. The slow fade is also colour-dependent and points to circumstellar material⁠[[9]]. What has not been found is the source: a mechanism that makes dust in large, short-lived clumps around a mature star with no infrared excess, and that also accounts for the fade. TESS observations from 2019 to 2022 found no deep dips at all⁠[[10]]. Of the 8 questions on this site, 0 are answered. The most likely answer to “What blocks the light during the deep, irregular dips?”, not yet confirmed: clumps of fine dust orbiting the star, released by comets, planetesimals or other bodies close to it.

### Key questionsset by the editors

[**What blocks the light during the deep, irregular dips?** ](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76FJ6B8S/what-blocks-the-light-during-the-deep-irregular-dips)Most likely: clumps of fine dust orbiting the star, released by comets, planetesimals or other bodies close to it

[**What causes the slow fading of the star?** ](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76Z60339/what-causes-the-slow-fading-of-the-star)Most likely: a large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips

 [All 8 questions ](https://mysteriesdept.com/questions/key-questions?mystery=tabbys-star)

## What happened

Kepler observed the star almost continuously for four years. Most of the time the light curve is flat; the events fall mainly in two groups, an isolated deep dip in Quarter 8, midway through the mission, and a cluster of dips in Quarters 16 and 17, the last months, reaching about 20 per cent, with complex and asymmetric shapes and durations of days⁠[[1]]⁠[[11]]. The events have no period. Wright and Sigurdsson found the timings of the deepest dips consistent with being random⁠[[6]].

[![Kepler light curve of KIC 8462852 (2009–2013)](https://mysteriesdept.com/files/v/b4bddfdfab04b2f96fe543d401aefe1a1553237a4786d517bdee340b2fd981de/w800)](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7PBC18ZC/kepler-light-curve-of-kic-8462852-20092013)

Kepler light curve of KIC 8462852 (2009–2013)JohnPassos (Wikimedia Commons), 2009. CC BY-SA 4.0[Artifact ](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7PBC18ZC/kepler-light-curve-of-kic-8462852-20092013)

Planet Hunters volunteers drew attention to the star, and Boyajian and colleagues reported it in 2015 as "where's the flux?". They showed the dips were in the star's light and not an artefact, that the star is an F-type main-sequence star, and that it has no infrared excess of the kind a massive dust disk would produce⁠[[1]]. Spitzer and ground-based infrared observations later in 2015 confirmed the absence of warm dust⁠[[12]]⁠[[13]].

After Kepler, the star was watched from the ground. In May 2017 it began a series of new dips, the first since 2013, and dipped repeatedly until it moved out of view at the end of the year⁠[[7]]. TESS has since observed it in seven sectors between 2019 and 2024. Nothing like the Kepler or 2017 dips has recurred, but Sector 15 holds a single symmetric dip of 1.1 per cent lasting about 0.7 days on 3 September 2019, which a 2026 radial-velocity study reads as the transit of a giant planet on an orbit of 1,000 days or more⁠[[14]]⁠[[15]].

**Map of the continent** [Open the full map](https://mysteriesdept.com/mysteries/tabbys-star/map)

[+][−]

1

**Harvard College Observatory plate stacks, Cambridge, Massachusetts** Archive

Within 1 km

2

**W. M. Keck Observatory, Maunakea, Hawaii** Observatory

Mapped

MappedWithin 1 kmNatural Earth

### Timeline

**Timeline**

Squeezed where little happened. Each mark is a published claim, by how it stands:AcceptedMost likelyStill possibleDisputedRuled out

## The accounts

The record is instrumental, and the accounts are the papers that interpret it. They fall into four threads.

**The dips.** The discovery paper is the reference description of the Kepler events⁠[[1]]. Bodman and Quillen fitted them with swarms of comets⁠[[11]]; Neslušan and Budaj with four dust-shrouded bodies on one orbit⁠[[16]]; Kiefer and colleagues found two near-identical dips 928 days apart⁠[[17]]; Ballesteros and colleagues proposed Trojan swarms on a 12-year orbit and predicted a return in 2021⁠[[18]]; Sacco and colleagues a 1,574-day period with a return in October 2019⁠[[19]]; Bourne, Gary and Plakhov a ringed brown dwarf with a repeat on 27 December 2021⁠[[20]]. The 2017 campaign, run mainly on the Las Cumbres network by a team of about two hundred authors, named the dips Elsie, Celeste, Skara Brae and Angkor and showed them deeper in blue than red⁠[[7]]; Deeg and colleagues confirmed the colour with the Gran Telescopio Canarias⁠[[8]]; Hitchcock and colleagues saw a month-long colour-dependent brightening after one dip⁠[[21]]. In 2026 three papers returned to the TESS record: Madurga-Favieres and colleagues modelled the 2019 symmetric dip with radial velocities as a planet of about nine Jupiter masses⁠[[14]], Zhu and colleagues fitted it with a ringed planet⁠[[15]], and Socas-Navarro found a Bayes factor of about 45 for recurrence of the dip families at 782 ± 80 days⁠[[22]].

**The fade in the Kepler era and after.** Montet and Simon measured it in the Kepler full-frame images⁠[[4]]. Meng and colleagues followed it from the ultraviolet to the mid-infrared in 2015-16 and found its colour shallower than interstellar extinction⁠[[9]]; Davenport and colleagues found a matching 3 per cent drop in GALEX ultraviolet between 2011 and 2012⁠[[23]]. Simon and colleagues showed from ASAS and ASAS-SN that the star's brightness since 2006 has wandered rather than declined steadily: brighter in 2006-07, fainter in 2009-13, brighter around 2014, fainter again at 6 mmag per year in 2015-17⁠[[24]]; Hippke and Angerhausen showed the year-long variations cannot be cyclic with a period under ten years⁠[[25]]. Schaefer and colleagues followed the decline in four colours to early 2018⁠[[26]]. No published measurement extends the fade past 2018.

**The century fade.** Schaefer measured 1,338 Harvard plate magnitudes from 1890 to 1989 and reported a fade of 0.164 mag per century with flat check stars⁠[[2]]. Hippke and colleagues measured the long-term stability of the same archive, found a structural break at 1962 rather than a trend, and put the systematic floor at 0.15-0.2 mag per century⁠[[3]]; Schaefer replied that their comparison stars were crowded and mixed emulsions⁠[[27]]. Lund and colleagues extended the test to 644 F stars and found the population's slopes well behaved only once a jump across the 1953-1969 "Menzel gap" in plate-taking is modelled⁠[[28]]. Three independent archives were then consulted: Sonneberg and Sternberg plates gave the star constant to 0.03-0.04 mag per century from 1934⁠[[29]]; Maria Mitchell Observatory plates gave +0.12 ± 0.02⁠[[30]]. The Harvard archive was wholly reprocessed as DASCH Data Release 7 in 2024⁠[[31]]⁠[[32]], and this department's re-analysis of DR7 against matched comparison stars is recorded under the question below.

**The explanations.** Wright and Sigurdsson's survey of the families of solutions, and Wright's 2018 reassessment after the colour results, are the clearest statements of what the readings are and how each is constrained⁠[[6]]⁠[[33]]. Wyatt and colleagues showed one exocomet population can produce both dips and the Kepler-era fade, and that a century fade must have ended before 2010⁠[[34]]; Metzger, Shen and Stone proposed recovery from swallowing a planet⁠[[35]], and Martinez, Stone and Metzger an evaporating exomoon left over from such a collision⁠[[36]]; Foukal proposed an intrinsic change in the star's convective flux⁠[[37]]; Shestakova and colleagues bodies falling in and breaking up⁠[[38]]. The bound companion was disputed⁠[[39]] and then confirmed with five years of Keck astrometry⁠[[40]]; Young and Wyatt tested whether it could drive comets inward and found the odds about one in a thousand⁠[[41]].

## What was recorded

The core data are public. The Kepler long-cadence light curves (30-minute sampling) for all 18 quarters and the full-frame images, from which the four-year fade was measured, are in the Mikulski Archive for Space Telescopes⁠[[42]]⁠[[4]]. TESS recorded the star at 2-minute cadence in Sectors 14 and 15 (2019), 41 (2021), 54 and 55 (2022), and in full-frame images in Sectors 75, 81 and 82 (2024)⁠[[42]]. Yang and Satarla stitched and detrended the 2019 to 2022 2-minute data with a half-day window and found no dip deeper than 0.5 per cent⁠[[10]]; with a three-day window the same data show the 1.1 per cent symmetric dip of 3 September 2019, and the 2024 sectors show nothing to 0.5 per cent at durations of a quarter to one day.

The colour information comes from the 2017 dips: multi-band photometry from Las Cumbres and other telescopes⁠[[7]], and spectrophotometry from the Gran Telescopio Canarias showing the dips deeper in blue than in red with an absorption coefficient that fits grains of about 0.0015 to 0.15 micron⁠[[8]]. One deep dip was followed by a colour-dependent brightening lasting about a month⁠[[21]]. The slow fade was measured from the ultraviolet to the mid-infrared from 2015 to 2016, at about 22 mmag per year with Swift and about 5 mmag per year at 3.6 to 4.5 microns⁠[[9]], and continued, at a varying rate, to 2018⁠[[26]]. Since 2018 the only ground record is the AAVSO database and ASAS-SN; ZTF saturates on a star this bright and Gaia DR3 published no epoch photometry for it.

[![Ground-based photometry of the 2017 dips](https://mysteriesdept.com/files/v/5fd72b29d16eaa5e68d365ec1268943a48ddbeaf5e8757c0d1f4388418c4c683/w800)](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7QJE3QH3/ground-based-photometry-of-the-2017-dips)

Ground-based photometry of the 2017 dipsBruce L. Gary, Hereford Arizona Observatory, 2017. CC0[Artifact ](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7QJE3QH3/ground-based-photometry-of-the-2017-dips)

The long history is in the Harvard plate collection, now served only as DASCH Data Release 7, which gives 2,717 detections of the star between 1890 and 1990⁠[[31]]. Sonneberg (1934-1995), Sternberg (1895-1995) and Maria Mitchell (1922-1991) plates have each been measured once⁠[[29]]⁠[[30]]. The star has a faint companion about 2 arcseconds away, confirmed in 2021 as a bound M dwarf at about 880 au⁠[[40]]. Radio and optical searches for technosignatures found nothing: no narrowband radio signal above 180 to 300 Jy in a 1 Hz channel between 1 and 10 GHz⁠[[43]] and no optical laser pulses⁠[[44]].

## The explanations

Circumstellar dust in clumps is the explanation the colour data support. A dip deeper in blue than red means the occulter scatters short wavelengths more, which fine dust does and solid bodies, planets or opaque panels do not⁠[[7]]⁠[[8]]. The grains implied are small enough to be pushed out of the system by starlight, so they must be renewed within days by something travelling with them⁠[[8]]. Candidate sources include a family of comets from a broken-up body, which can reproduce depths and durations of the later Kepler dips with tens to hundreds of large comets but not the Quarter 8 dip⁠[[11]]; Trojan swarms around a ringed planet, which predicted a return in 2021⁠[[18]]; bodies falling towards the star and breaking up⁠[[38]]; and debris from a planet the star has swallowed⁠[[35]]⁠[[36]]. Driving comets inward by the bound companion through the eccentric Kozai-Lidov mechanism was tested and found to have a probability of about one in a thousand of producing one such star in the Kepler field⁠[[41]]. The 2019 symmetric dip is a different kind of event, and if it is a planetary transit⁠[[14]]⁠[[15]] the system has a giant planet whose orbit the dust models will have to accommodate.

The slow fade is the harder part. Meng and colleagues found its colour dependence less steep than interstellar reddening and attributed it to circumstellar dust⁠[[9]]. Metzger and colleagues proposed that the star is recovering from swallowing a planet⁠[[35]]. Wright and Sigurdsson rated an intervening cloud in the interstellar medium, or an object with a large disk between us and the star, as the most plausible natural explanations for dips and fade together⁠[[6]]. The Kepler and post-Kepler fades rest on other instruments and are not in doubt⁠[[4]]⁠[[9]], though since 2006 the brightness has gone up as well as down⁠[[24]].

Whether the star also faded through the twentieth century is still open, and the department's DASCH DR7 re-analysis says why. The 0.166 mag per century slope is reproduced, and against 49 comparison stars of the same brightness and colour on the same plates, screened for neighbours, the star has the steepest slope and the largest offset across the 1953-1969 gap; but it is only about 2 sigma above them (one star in 49 is steeper), the comparison stars share a drift of +0.03 mag per century, and the star's own record is flat from 1890 to 1953. The signal is a drop of about 0.07 mag between the 1950s and the 1970s beyond what matched stars show, not a steady century-long fade⁠[[2]]⁠[[3]]⁠[[28]]. Independent archives disagree about even that: Sonneberg sees no step⁠[[29]], Maria Mitchell sees a steady fade⁠[[30]].

Intrinsic variability of the star was left open by the 2017 campaign, which noted that its data might also be consistent with variations in the photosphere⁠[[7]]; Foukal's convective-flux model is the one worked-out version⁠[[37]], and no known stellar process reproduces the whole light curve⁠[[4]]. Artificial megastructures were proposed as a hypothesis to be tested, not a conclusion, and predicted grey (colour-independent) dips for large opaque structures⁠[[5]]. The chromatic dips and the null technosignature searches have removed most of the support for that reading⁠[[7]]⁠[[43]].

### Published claims

**Published claims and their status**

| Year | Who | Claimed | Status | Reason |
|---|---|---|---|---|
| 2016 | Tabetha Boyajian and the Planet Hunters team⁠[1] | The irregular dips of up to 20 per cent are not instrumental and are best explained by a family of comet or planetesimal fragments. | Most likely | Later work confirmed the dips are caused by fine dust, but which bodies release it is still argued⁠[7]⁠[11]. |
| 2016 | Jason Wright and colleagues⁠[5] | The light curve is the kind large artificial structures transiting a star would produce, so the star is a target for a megastructure test. | Ruled out | Two independent measurements found the 2017 dips deeper in blue than red, as fine dust dims a star and opaque structures do not⁠[7]⁠[8]. |
| 2016 | Gerald Harp and colleagues, SETI Institute⁠[43] | The Allen Telescope Array found no narrowband or medium-band radio signals from the star between 1 and 10 GHz. | Accepted | The search is published with its limits, and no later search has reported a signal⁠[43]. |
| 2016 | Bradley Schaefer⁠[2] | Harvard plates show the star faded by about 0.16 magnitudes per century from 1890 to 1989. | Disputed | DASCH DR7 reproduces the slope, but matched comparison stars put it at about 2 sigma, and the record is flat before 1953⁠[3]⁠[28]. |
| 2016 | Michael Hippke and colleagues⁠[3] | Plate photometry drifts by up to 0.2 magnitudes per century for most constant stars, and the target shows a break at 1962 rather than a trend. | Disputed | In DR7 matched, uncrowded stars scatter by 0.07 mag per century, less than the 0.15-0.2 quoted, and the target sits at the top of them⁠[27]. |
| 2016 | Michael Lund and colleagues⁠[28] | Across 644 F stars, apparent century slopes are an artefact of the 1953-1969 Menzel gap, and KIC 8462852 is consistent with constant flux once the gap is modelled. | Disputed | DR7 confirms the structure: the target's pre-1953 slope is 0.02 ± 0.05, and the whole signal is the offset across the gap⁠[3]. |
| 2017 | Michael Hippke and colleagues (Sonneberg)⁠[29] | Sonneberg and Sternberg plates show the star constant to 0.03-0.04 mag per century from 1934 to 1995, rejecting the 0.164 fade at about 5 sigma. | Accepted | Independent of Harvard's emulsions; disagrees with the Maria Mitchell result at about 3 sigma⁠[30]. |
| 2018 | Michael Castelaz and Thurburn Barker⁠[30] | Maria Mitchell Observatory plates from 1922 to 1991 show a fade of 0.12 ± 0.02 mag per century. | Accepted | Only eight comparison stars and no formal systematic budget; the one archive that agrees with Schaefer⁠[29]. |
| 2016 | Benjamin Montet and Joshua Simon⁠[4] | The star faded by about 0.34 per cent a year for 1,000 days of the Kepler mission, then by more than 2 per cent in 200 days. | Accepted | None of hundreds of comparison stars behaves this way, and ground and space monitoring found the decline continuing⁠[9]⁠[26]. |
| 2018 | Joshua Simon and colleagues⁠[24] | The star faded at 6.3 ± 1.4 mmag per year in 2015-17, and since 2006 has brightened and dimmed by a few per cent on timescales of years. | Accepted | The most extreme of 1,078 ASAS-SN comparison stars; shows the fade is not a straight line⁠[25]. |
| 2016 | Eva Bodman and Alice Quillen⁠[11] | A swarm of comets from one broken body fits the last 60 days of Kepler dips but not the deepest earlier ones. | Still possible | The model fits part of the light curve, and the source of the dust remains open⁠[40]. |
| 2016 | Jason Wright and Steinn Sigurdsson⁠[6] | The dips and fade may come from material between us and the star, such as structure in the interstellar medium, rather than material orbiting it. | Still possible | The fade's wavelength dependence is less steep than interstellar extinction, which points to circumstellar material, but intervening matter is not excluded⁠[9]. |
| 2017 | Huan Meng and colleagues⁠[9] | The long-term dimming is caused by circumstellar dust, since it is shallower with wavelength than interstellar extinction. | Most likely | It fits the chromatic dips and the GALEX ultraviolet drop, though a planet-engulfment reading of the fade has not been excluded⁠[23]⁠[35]. |
| 2017 | Brian Metzger, Ken Shen and Nicholas Stone⁠[35] | The star swallowed a planet, and the slow fade is it returning to normal after the brightening; debris from the planet's moons makes the dips. | Disputed | The fade's colour points to dust, which the engulfment model has to add rather than predict⁠[9]. |
| 2018 | Mark Wyatt and colleagues⁠[34] | One population of exocomets on an eccentric orbit can produce both the dips and the Kepler-era fade; a 16 per cent century fade must have ended before 2010. | Still possible | The one model that treats dips and fade together quantitatively; its century-fade constraint depends on the plates⁠[2]. |
| 2017 | Peter Foukal⁠[37] | The decadal dimming is the star storing convective flux in its outer layers; the dips' reddening is a cooling of about 30 K. | Disputed | The only intrinsic model worked through; the spectrum and polarisation did not change during the 2017 dips⁠[7]. |
| 2017 | Fernando Ballesteros and colleagues⁠[18] | A ringed planet with Trojan swarms of debris on a long orbit causes the dips, which will return in 2021. | Disputed | TESS did not observe the star in late 2021, so the predicted window was not covered⁠[10]. |
| 2018 | Gary Sacco, Linh Ngo and Julien Modolo⁠[19] | The dips recur every 1,574 days and were due to return in October 2019. | Disputed | TESS Sector 15 ended on 10 September 2019; the 3 September dip falls a month before the predicted window and is of a different kind⁠[14]. |
| 2018 | Tabetha Boyajian and colleagues⁠[7] | The 2017 dips are deeper in blue than in red light, so they are caused by fine dust, not by opaque bodies. | Accepted | Independent spectrophotometry from the Gran Telescopio Canarias found the same colour dependence⁠[8]. |
| 2018 | Hans Deeg and colleagues⁠[8] | The 2017 dips are consistent with optically thin dust of grains smaller than about 0.15 microns. | Accepted | It agrees with the multi-band photometry of the same dips⁠[7]. |
| 2021 | Logan Pearce and colleagues⁠[40] | A faint star 880 au away is a bound companion, and it may drive the bodies whose debris makes the dips. | Disputed | The companion is firmly established, but a model of the mechanism found it too improbable to explain the star⁠[41]. |
| 2021 | Lyubov Shestakova and colleagues⁠[38] | The dips are dust from bodies falling towards the star and destroyed by its heat. | Still possible | It is one modelling paper, and later observations have not been compared with it in the sources this record holds⁠[38]. |
| 2023 | Steven Young and Mark Wyatt⁠[41] | The companion driving comets onto star-grazing orbits is too improbable, at about 1.3 in 1,000 for the Kepler field, to explain the star. | Accepted | It is the only quantitative test of the mechanism and has not been answered⁠[41]. |
| 2026 | Edison Yang and Rithik Satarla⁠[10] | TESS photometry from 2019 to 2022 shows no dips deeper than 0.5 per cent and nothing like the 2017 events. | Disputed | The half-day detrending window removes day-long dips; the same data hold a 1.1 per cent, 0.7-day dip on 3 September 2019⁠[14]. |
| 2026 | Cristina Madurga-Favieres and colleagues⁠[14] | The symmetric 1.1 per cent dip of September 2019 is the transit of a planet of about nine Jupiter masses on an orbit of 1,000 days or more. | Still possible | A 2.3-sigma radial-velocity signal and a single transit; the predicted return windows have not yet been observed⁠[15]. |
| 2026 | Hector Socas-Navarro⁠[22] | The dip families recur at 782 ± 80 days, with a Bayes factor of about 45 for recurrence over randomness. | Still possible | A statistical recurrence test on the dip families, not a transit model; testable against future TESS sectors⁠[14]. |

## What would settle it

A deep dip observed with spectroscopy across a wide wavelength range would measure the dust directly: its grain size, composition and the gas, if any, that comes with it. A comet family predicts water and carbon monoxide gas and grains of a cometary mix; debris from a destroyed planet predicts rock-forming silicates; an intervening interstellar cloud predicts sodium and other absorption lines that change during dips.

The 2019 symmetric dip gives the first dated prediction on this star that can be checked: the allowed orbital periods of Madurga-Favieres and colleagues and the 782-day recurrence of Socas-Navarro each name future transit windows, and TESS returns to the field in 2027⁠[[14]]⁠[[22]]. A second transit at a predicted time would establish the planet; an observed window with none would retire it.

For the century fade, more Harvard statistics will not do it. What would is agreement between archives: the Sonneberg, Sternberg and Maria Mitchell plates reduced with the same matched-comparison method and tested for a 0.07-0.10 mag step between the 1950s and the 1970s; and, on the Harvard side, a per-plate differential against stars within a few arcminutes using DR7's measured colour terms and a Gaia neighbour screen, to rule out a blend on the coarse post-1962 patrol plates⁠[[31]]. For the modern fade, the 2018-2026 ground record (AAVSO, ASAS-SN) has never been reduced; eight more years would show whether the 6 mmag per year decline continued or reversed⁠[[24]]. A population of analogue stars would turn a single case into a statistical problem; a survey for analogues has so far published two lists of candidates⁠[[45]]⁠[[46]].

## Questions

0 of 8 questions are answered.

**Key questions** [All 8](https://mysteriesdept.com/questions/key-questions?mystery=tabbys-star)

 **0**

[What blocks the light during the deep, irregular dips?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76FJ6B8S/what-blocks-the-light-during-the-deep-irregular-dips)

0 of 3 sub-questions answered·0

Most likely: clumps of fine dust orbiting the star, released by comets, planetesimals or other bodies close to it



 **0**

[What causes the slow fading of the star?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76Z60339/what-causes-the-slow-fading-of-the-star)

0 of 2 sub-questions answered·0

Most likely: a large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips



## Evidence 39 findings

[What blocks the light during the deep, irregular dips?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76FJ6B8S/what-blocks-the-light-during-the-deep-irregular-dips)13 findings

[Clumps of fine dust orbiting the star, released by comets, planetesimals or other bodies close to it.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E77PM4YKA/clumps-of-fine-dust-orbiting-the-star-released-by-comets)Most likely

+[The 2017 dips were deeper in blue than red with no change in spectrum or polarisation; the authors favour optically thin dust with grains much smaller than 1 micron.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E77YE7HJZ/the-2017-dips-were-deeper-in-blue-than-red-with-no-change-in)Established

+[GTC spectrophotometry gives an Ångström coefficient of 2.19 ± 0.45, consistent with grains of 0.0015 to 0.15 micron.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E78684PK7/gtc-spectrophotometry-gives-an-angstrom-coefficient-of-2-19)Supported

−[There is no infrared excess, so there is no large reservoir of warm dust near the star.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E78E225F1/there-is-no-infrared-excess-so-there-is-no-large-reservoir)Supported

−[Grains this small are blown out by radiation pressure and must be renewed from a comoving body within days.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E78NW28RW/grains-this-small-are-blown-out-by-radiation-pressure-and)Suggestive

[Material between us and the star, not bound to it, such as structure in the interstellar medium or a small…](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E78XP0036/material-between-us-and-the-star-not-bound-to-it-such-as)Still possible

+[The timings of the deepest dips are consistent with being random.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E795G77MH/the-timings-of-the-deepest-dips-are-consistent-with-being)Supported

+[Wright and Sigurdsson rate the interstellar-medium and intervening-disk models as the most plausible natural ones.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E79DA0E5M/wright-and-sigurdsson-rate-the-interstellar-medium-and)Suggestive

−[Dip ingress and egress times of days fit material moving at orbital speeds close to the star better than a distant cloud.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E79N41XT9/dip-ingress-and-egress-times-of-days-fit-material-moving-at)Speculative

[Variability of the star itself, for example in its photosphere, rather than an occulter.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E79WY03MS/variability-of-the-star-itself-for-example-in-its)Disputed

+[The 2017 campaign notes its data may also be consistent with variations intrinsic to the photosphere.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7A4R7ZM3/the-2017-campaign-notes-its-data-may-also-be-consistent-with)Speculative

−[No change in the stellar spectrum or polarisation was seen during the 2017 dips.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7ACJ4717/no-change-in-the-stellar-spectrum-or-polarisation-was-seen)Supported

−[No known or proposed stellar phenomenon explains all aspects of the light curve.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7AMC4ZZR/no-known-or-proposed-stellar-phenomenon-explains-all-aspects)Supported

[Large artificial structures orbiting the star.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7AW65TQF/large-artificial-structures-orbiting-the-star)Disputed

−[The 2017 dips were chromatic, which large opaque structures would not produce.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7B4010M5/the-2017-dips-were-chromatic-which-large-opaque-structures)Established

−[The Allen Telescope Array found no narrowband signal above 180 to 300 Jy in a 1 Hz channel from 1 to 10 GHz.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7BBT588K/the-allen-telescope-array-found-no-narrowband-signal-above)Supported

−[No optical laser signals were detected.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7BKM2CZ5/no-optical-laser-signals-were-detected)Suggestive

[If the dips are dust, what produces it in large, short-lived clumps?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76QC6BDA/if-the-dips-are-dust-what-produces-it-in-large-short-lived)6 findings

[The fragments of a broken-up comet or planetesimal on an eccentric orbit, passing in front of the star in…](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7C3815EN/the-fragments-of-a-broken-up-comet-or-planetesimal-on-an)Most likely

+[A cluster of about 30 comets of 100 km radius, or 300 of 10 km, reaches a 20 per cent depth; one family from a disrupted Ceres-sized body fits the last 60 days of Kepler data.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7CB234XD/a-cluster-of-about-30-comets-of-100-km-radius-or-300-of-10)Suggestive

−[The same comet-family model does not explain the large Quarter 8 dip.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7CJW2VVB/the-same-comet-family-model-does-not-explain-the-large)Supported

−[The century fade, if real, would need about 648,000 giant comets in a century.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7CTP038F/the-century-fade-if-real-would-need-about-648-000-giant)Suggestive

[Comets driven onto star-grazing orbits by the bound M-dwarf companion through the eccentric Kozai-Lidov…](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7D2G4BMZ/comets-driven-onto-star-grazing-orbits-by-the-bound-m-dwarf)Disputed

+[The companion is bound, at 880 ± 10 au projected separation.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7DAA3Y7C/the-companion-is-bound-at-880-10-au-projected-separation)Established

−[A Monte Carlo model gives a probability of about 1.3 × 10⁻³ of seeing one or more such stars in the Kepler field.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7DJ47PS0/a-monte-carlo-model-gives-a-probability-of-about-1-3-103-of)Supported

[Swarms of debris at the Trojan points of a ringed planet on a long orbit.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7DSY0V6T/swarms-of-debris-at-the-trojan-points-of-a-ringed-planet-on)Disputed

−[TESS 2-minute data in July and August 2021 (Sector 41) show no dips deeper than 0.5 per cent.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7E1R3QHS/tess-2-minute-data-in-july-and-august-2021-sector-41-show-no)Suggestive

[What causes the slow fading of the star?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76Z60339/what-causes-the-slow-fading-of-the-star)5 findings

[A large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7F100DFT/a-large-diffuse-amount-of-circumstellar-dust-more-extended)Most likely

+[The fade from 2015 to 2016 is about 22 mmag per year in Swift bands and about 5 mmag per year at 3.6 to 4.5 microns, a colour law less steep than the ISM's.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7F8T7ESC/the-fade-from-2015-to-2016-is-about-22-mmag-per-year-in)Supported

+[The secular decline continued to 2018 at a varying rate.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7FGM0BJM/the-secular-decline-continued-to-2018-at-a-varying-rate)Suggestive

[The star is returning to normal after swallowing a planet, which brightened it.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7FRE3X1F/the-star-is-returning-to-normal-after-swallowing-a-planet)Disputed

−[The fade's colour dependence is consistent with circumstellar material.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7G0841N6/the-fades-colour-dependence-is-consistent-with-circumstellar)Suggestive

[An interstellar cloud or other intervening material passing slowly across the line of sight.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7G821ZQ6/an-interstellar-cloud-or-other-intervening-material-passing)Disputed

+[The star's reddening and narrow sodium absorption are consistent with the total long-term dimming.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7GFW0926/the-stars-reddening-and-narrow-sodium-absorption-are)Suggestive

−[The fade is less steep in wavelength than general interstellar extinction.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7GQP3E98/the-fade-is-less-steep-in-wavelength-than-general)Suggestive

[Did the star fade over the twentieth century?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E77702V2V/did-the-star-fade-over-the-twentieth-century)10 findings

[The star faded by about 0.16 magnitudes per century from 1890 to 1989.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7H7A1MXP/the-star-faded-by-about-0-16-magnitudes-per-century-from)Disputed

+[1,338 B-band magnitudes show a fade of 0.193 ± 0.030 mag while nearby check stars are flat.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7HF426QH/1-338-b-band-magnitudes-show-a-fade-of-0-193-0-030-mag-while)Suggestive

+[In DASCH DR7 the star's slope is +0.166 ± 0.020 mag per century (895 clean detections, 1890-1990), and against 49 uncrowded comparison stars of the same magnitude and colour it ranks first (98th percentile, z = 2.0); the plate-differential slope against those stars is +0.133 ± 0.021 and again ranks first (z = 2.0).](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF8B807DJ/dr7-reproduces-the-0-17-mag-century-slope-and-the-target-is)Suggestive

+[On 835 Maria Mitchell Observatory plates from 1922 to 1991, reduced against eight APASS comparison stars, the star fades by +0.12 ± 0.02 mag per century in 5-year bins while six of the eight comparison stars are flat within 0.04.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYFABS34WD/maria-mitchell-observatory-plates-give-an-independent-0-12)Supported

−[In DR7 the star's slope within 1890-1953 is +0.02 ± 0.05 mag per century (543 points) and within 1969-1990 it is unconstrained (+0.25 ± 0.19); the full-span slope is produced by a 0.088 mag offset between the 1930-1953 and 1969-1990 levels, so the fade was not steady.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF8MTYR79/the-pre-1953-record-is-flat-the-slope-comes-from-the-post)Supported

−[Sonneberg Sky Patrol plates (1934-1995, two passbands) and Sternberg plates (1895-1995) give slopes of -0.006 ± 0.032 and -0.046 ± 0.040 mag per century, rejecting 0.164 at about 5 sigma.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYFAJKXP2D/sonneberg-and-sternberg-plates-show-the-star-constant-to-0)Supported

[The century fade is a calibration artefact of plate photometry.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7HPY1BFW/the-century-fade-is-a-calibration-artefact-of-plate)Disputed

+[DASCH photometry has systematics of up to about 0.2 mag per century for most constant stars, so the trend is not significant.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7HYR3BHP/dasch-photometry-has-systematics-of-up-to-about-0-2-mag-per)Suggestive

+[Forty-nine uncrowded comparison stars matched to the target in magnitude and colour have century slopes with mean +0.034 and standard deviation 0.068 mag per century in DR7, so the systematic floor is larger than the 0.044 rms Schaefer measured from his check stars, and his 4-sigma claim becomes about 2 sigma.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF91D8RN9/matched-constant-stars-in-dr7-scatter-by-0-07-mag-century)Supported

−[The target is 0.088 mag fainter after 1969 than in 1930-1953, while the 49 matched stars shift by only +0.020 ± 0.034 mag on the same plates; the target's offset is the largest of the fifty (z = 2.0), so the Menzel-gap step is not simply a plate-series zero-point error common to its neighbours.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF9DGSEKW/matched-stars-do-not-share-the-targets-post-1969-offset)Suggestive

[A single drop of about 0.1 mag across the 1953-1969 plate gap, not a steady century fade](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0DDYETY1NV0T/a-single-drop-of-about-0-1-mag-across-the-1953-1969-plate)Still possible

+[In DR7 the target's slope is +0.02 ± 0.05 mag per century before 1953 and its level after 1969 is 0.088 mag fainter, an offset the 49 matched stars reproduce only at the +0.02 ± 0.03 level; Hippke et al. and Lund et al. found the same break structure in the 2016 release.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYFA2QEREK/both-halves-of-the-harvard-record-are-flat-and-the-offset)Suggestive

−[Differential photometry of 861 Sonneberg pg plates against 39 colour-matched comparison stars gives a 1934-1995 slope of -0.006 ± 0.032 mag per century with continuous coverage through the Harvard gap, which leaves no room for a 0.1 mag drop between the 1950s and the 1970s.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF9R189DE/sonneberg-plates-covering-1934-1995-show-no-step-and-no-fade)Supported

[Has the dipping stopped, or does it come in episodes?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E77ET2CAQ/has-the-dipping-stopped-or-does-it-come-in-episodes)5 findings

[Dipping comes in episodes separated by years of quiet, with no strict period.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7JEC0TJR/dipping-comes-in-episodes-separated-by-years-of-quiet-with)Most likely

+[Dips occurred in the Kepler years and again in 2017, with quiet between.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7JP67TD3/dips-occurred-in-the-kepler-years-and-again-in-2017-with)Established

[The dipping recurs on a long orbital period.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7JY053WH/the-dipping-recurs-on-a-long-orbital-period)Disputed

−[The deepest dip timings are consistent with random.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7K5T2W9M/the-deepest-dip-timings-are-consistent-with-random)Suggestive

[The activity that produced the dips has ended or declined.](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0D8E7KDM7HCY/the-activity-that-produced-the-dips-has-ended-or-declined)Still possible

+[No dips deeper than 0.5 per cent and shorter than about half a day in TESS data from July 2019 to September 2022; the 0.56-day detrending window used does not test day-long dips, and one such dip of 1.1 per cent is present in Sector 15.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7KNE02N0/no-dips-deeper-than-0-5-per-cent-shorter-than-about-half-a)Suggestive

+[In TESS Sectors 81 and 82 (QLP detrended flux, 24 July to 20 August 2024) the deepest feature at 0.25-1 day durations is 0.12 per cent at SNR 4.2, with injection-recovery of 90-100 per cent for 0.5 per cent dips of 0.5-1 day, so the dip-free record now runs from July 2019 to August 2024 at that level.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYFG8VM2NN/no-dips-to-0-5-per-cent-in-the-2024-tess-sectors-81-and-82)Supported

−[TESS Sector 15 SPOC photometry holds a symmetric dip of 1.11 per cent centred at BTJD 1730.12 (2019-09-03 14:55 UTC), about 0.7 days from first to last contact, present in both SAP and PDCSAP flux with flat background, at SNR 76 in a 3-day-detrended search; it is the event Madurga-Favieres et al. and Zhu et al. model as a planetary transit.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYFGRCSV6G/a-1-1-per-cent-symmetric-dip-on-3-september-2019-in-tess)Supported

## Artifacts

The films, photos, papers and objects this mystery rests on, each with its own key and its distance from the original.

**Artifacts** [See all 12](https://mysteriesdept.com/mysteries/tabbys-star/artifacts)

Scan1 step from object

[Harvard College Observatory photographic plates showing KIC 8462852](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7NKY0A11/harvard-college-observatory-photographic-plates-showing-kic)

DASCH project · Harvard terms of use

Document2 steps from object

[Kepler light curve of KIC 8462852 (2009–2013)](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7PBC18ZC/kepler-light-curve-of-kic-8462852-20092013)

JohnPassos (Wikimedia Commons) · CC BY-SA 4.0

Dataset1 step from object

[Kepler full-frame images covering KIC 8462852](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7Q2T61CQ/kepler-full-frame-images-covering-kic-8462852)

NASA Kepler mission · public-domain

Document1 step from object

[Ground-based photometry of the 2017 dips](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7QJE3QH3/ground-based-photometry-of-the-2017-dips)

Bruce L. Gary, Hereford Arizona Observatory · CC0

Document2 steps from object

[TESS light curves of KIC 8462852 (2019–2024)](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7R9W3J21/tess-light-curves-of-kic-8462852-20192024)

Yang and colleagues · CC-BY-4.0

Document2 steps from object

[Keck adaptive-optics images of KIC 8462852 and its companion](https://mysteriesdept.com/mysteries/tabbys-star/artifacts/ART0D8E7S1A6B82/keck-adaptive-optics-images-of-kic-8462852-and-its-companion)

Pearce and colleagues · publisher

 [See all 12 artifacts](https://mysteriesdept.com/mysteries/tabbys-star/artifacts)

## See also

 [

**HD 139139, the "Random Transiter"** A Sun-like star whose light dipped 28 times at random in 87 days of K2 data in 2017.

](https://mysteriesdept.com/mysteries/hd-139139-random-transiter) [

**Wow! signal** A 72-second radio signal recorded by Ohio State's Big Ear telescope in August 1977.

](https://mysteriesdept.com/mysteries/wow-signal) [

**Phosphine in the clouds of Venus** A 2020 report of phosphine gas in the clouds of Venus, not independently confirmed.

](https://mysteriesdept.com/mysteries/venus-phosphine) [

**Mars methane puzzle** Methane reported at Gale crater by the Curiosity rover but not seen from orbit.

](https://mysteriesdept.com/mysteries/mars-methane)

## References

1. 1.[Boyajian, T., LaCourse, D., Rappaport, S. et al. 2016. Planet Hunters IX. KIC 8462852 – where's the flux?. Monthly Notices of the Royal Astronomical Society 457(4), 3988–4004.](https://mysteriesdept.com/sources/SRC0D8E6TGR30ZB/planet-hunters-ix-kic-8462852-wheres-the-flux)[doi](https://doi.org/10.1093/mnras/stw218)cited 13 times here**SRC** 0D8E6TGR30ZB
1. 2.[Schaefer, B. 2016. KIC 8462852 Faded at an Average Rate of 0.164 ± 0.013 Magnitudes per Century from 1890 to 1989. The Astrophysical Journal Letters 822(2), L34.](https://mysteriesdept.com/sources/SRC0D8E6V0C3X81/kic-8462852-faded-at-an-average-rate-of-0-164-0-013)[doi](https://doi.org/10.3847/2041-8205/822/2/l34)cited 10 times here**SRC** 0D8E6V0C3X81
1. 3.[Hippke, M., Angerhausen, D., Lund, M. et al. 2016. A Statistical Analysis of the Accuracy of the Digitized Magnitudes of Photometric Plates on the Time Scale of Decades with an Application to the Century-long Light Curve of KIC 8462852. The Astrophysical Journal 825(1), 73.](https://mysteriesdept.com/sources/SRC0D8E6V860VNG/a-statistical-analysis-of-the-accuracy-of-the-digitized)[doi](https://doi.org/10.3847/0004-637x/825/1/73)cited 10 times here**SRC** 0D8E6V860VNG
1. 4.[Montet, B., Simon, J. 2016. KIC 8462852 Faded Throughout the Kepler Mission. The Astrophysical Journal Letters 830(2), L39.](https://mysteriesdept.com/sources/SRC0D8E6VG02Q16/kic-8462852-faded-throughout-the-kepler-mission)[doi](https://doi.org/10.3847/2041-8205/830/2/l39)cited 7 times here**SRC** 0D8E6VG02Q16
1. 5.[Wright, J., Cartier, K., Zhao, M. et al. 2016. The Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies. IV. The Signatures and Information Content of Transiting Megastructures. The Astrophysical Journal 816(1), 17.](https://mysteriesdept.com/sources/SRC0D8E6XPA3DBQ/the-g-search-for-extraterrestrial-civilizations-with-large)[doi](https://doi.org/10.3847/0004-637x/816/1/17)cited 2 times here**SRC** 0D8E6XPA3DBQ
1. 6.[Wright, J., Sigurdsson, S. 2016. Families of Plausible Solutions to the Puzzle of Boyajian's Star. The Astrophysical Journal Letters 829(1), L3.](https://mysteriesdept.com/sources/SRC0D8E6XEG2N4H/families-of-plausible-solutions-to-the-puzzle-of-boyajians)[doi](https://doi.org/10.3847/2041-8205/829/1/l3)cited 10 times here**SRC** 0D8E6XEG2N4H
1. 7.[Boyajian, T., Alonso, R., Ammerman, A. et al. 2018. The First Post-Kepler Brightness Dips of KIC 8462852. The Astrophysical Journal Letters 853(1), L8.](https://mysteriesdept.com/sources/SRC0D8E6TRJ1Q2M/the-first-post-kepler-brightness-dips-of-kic-8462852)[doi](https://doi.org/10.3847/2041-8213/aaa405)cited 15 times here**SRC** 0D8E6TRJ1Q2M
1. 8.[Deeg, H., Alonso, R., Nespral, D. et al. 2018. Non-grey dimming events of KIC 8462852 from GTC spectrophotometry. Astronomy & Astrophysics 610, L12.](https://mysteriesdept.com/sources/SRC0D8E6VZM0D8Z/non-grey-dimming-events-of-kic-8462852-from-gtc)[doi](https://doi.org/10.1051/0004-6361/201732453)cited 5 times here**SRC** 0D8E6VZM0D8Z
1. 9.[Meng, H., Rieke, G., Dubois, F. et al. 2017. Extinction and the Dimming of KIC 8462852. The Astrophysical Journal 847(2), 131.](https://mysteriesdept.com/sources/SRC0D8E6VQT23KR/extinction-and-the-dimming-of-kic-8462852)[doi](https://doi.org/10.3847/1538-4357/aa899c)cited 6 times here**SRC** 0D8E6VQT23KR
1. 10.[Yang, E., Satarla, R. 2026. No Deep Dimming Events in KIC 8462852 (Boyajian's Star) from TESS 2 minute Cadence Photometry, 2019–2022. Research Notes of the AAS 10(5), 115.](https://mysteriesdept.com/sources/SRC0D8E704E6NFA/no-deep-dimming-events-in-kic-8462852-boyajians-star-from)[doi](https://doi.org/10.3847/2515-5172/ae682d)cited 12 times here**SRC** 0D8E704E6NFA
1. 11.[Bodman, E., Quillen, A. 2016. KIC 8462852: Transit of a Large Comet Family. The Astrophysical Journal Letters 819(2), L34.](https://mysteriesdept.com/sources/SRC0D8E6X6P5TVA/kic-8462852-transit-of-a-large-comet-family)[doi](https://doi.org/10.3847/2041-8205/819/2/l34)cited 3 times here**SRC** 0D8E6X6P5TVA
1. 12.[Marengo, M., Hulsebus, A., Willis, S. 2015. KIC 8462852: The Infrared Flux. The Astrophysical Journal Letters 814(1), L15.](https://mysteriesdept.com/sources/SRC0D8E6WQ225MY/kic-8462852-the-infrared-flux)[doi](https://doi.org/10.1088/2041-8205/814/1/l15)cited 1 time here**SRC** 0D8E6WQ225MY
1. 13.[Lisse, C., Sitko, M., Marengo, M. 2015. IRTF/SpeX Observations of the Unusual Kepler Light Curve System KIC 8462852. The Astrophysical Journal Letters 815(2), L27.](https://mysteriesdept.com/sources/SRC0D8E6WYW5S7Q/irtf-spex-observations-of-the-unusual-kepler-light-curve)[doi](https://doi.org/10.1088/2041-8205/815/2/l27)cited 1 time here**SRC** 0D8E6WYW5S7Q
1. 14.[arXiv:2607.20643 (July 2026). Models the symmetric 1.1 per cent dip in TESS Sector 15 (September 2019) as a planetary transit and combines it with archival and new radial velocities: a 2.3-sigma companion of about 9 Jupiter masses and 1.7 Jupiter radii with a period of at least about 1030 days, in several allowed period windows. Independently recovered in this department's TESS search.](https://mysteriesdept.com/sources/SRC0DDYDQFQE9VW/evidence-for-a-giant-companion-orbiting-tabbys-star)cited 2 times here**SRC** 0DDYDQFQE9VW
1. 15.[arXiv:2610.34806 (October 2026). Fits the 2019 TESS transit with a 1.1 Jupiter-radius planet carrying a ring out to 3-4 planetary radii.](https://mysteriesdept.com/sources/SRC0DDYDRAN9FJQ/the-anomalously-large-transiting-planet-around-boyajians)cited 2 times here**SRC** 0DDYDRAN9FJQ
1. 16.[A&A 600, A86. Four bodies enshrouded in dust clouds on one orbit reproduce the shapes of the main Kepler dips.](https://mysteriesdept.com/sources/SRC0DDYDP8NPTQQ/mysterious-eclipses-in-the-light-curve-of-kic8462852-a)[doi](https://doi.org/10.1051/0004-6361/201629344)cited 1 time here**SRC** 0DDYDP8NPTQQ
1. 17.[A&A 608, A132. Finds 22 dips in Kepler data, two of them near-identical and 928.25 days apart, read as a ring system or a group of about six exocomets.](https://mysteriesdept.com/sources/SRC0DDYDNQD9HX8/detection-of-a-repeated-transit-signature-in-the-light-curve)[doi](https://doi.org/10.1051/0004-6361/201731306)cited 1 time here**SRC** 0DDYDNQD9HX8
1. 18.[Ballesteros, F., Arnalte-Mur, P., Fernandez-Soto, A. et al. 2017. KIC 8462852: Will the Trojans return in 2021?. Monthly Notices of the Royal Astronomical Society: Letters 473(1), L21–L25.](https://mysteriesdept.com/sources/SRC0D8E6YNJ60WX/kic-8462852-will-the-trojans-return-in-2021)[doi](https://doi.org/10.1093/mnrasl/slx105)cited 3 times here**SRC** 0D8E6YNJ60WX
1. 19.[JAAVSO 46. Aligns Kepler dips with the 2017 dips at a 1574-day period and predicted a return in October 2019. The TESS record from July 2019 (Sector 14-15) is the test.](https://mysteriesdept.com/sources/SRC0DDYDANPB1EK/a-1574-day-periodicity-of-transits-orbiting-kic-8462852)cited 1 time here**SRC** 0DDYDANPB1EK
1. 20.[MNRAS 475, 5378. Amateur V and g' monitoring 2014-2017; proposes a ringed brown dwarf on a 1601-day orbit and predicted a repeat of the day-1540 dip on 27 December 2021. A dated, falsifiable prediction for the periodic reading.](https://mysteriesdept.com/sources/SRC0DDYDAA4PGWQ/recent-photometric-monitoring-of-kic-8462852-the-detection)[doi](https://doi.org/10.1093/mnras/sty097)cited 1 time here**SRC** 0DDYDAA4PGWQ
1. 21.[Hitchcock, J., Fossey, S., Savini, G. 2019. Non-gray, Month-long Brightening of KIC 8462852 in the Immediate Aftermath of a Deep Dip. Publications of the Astronomical Society of the Pacific 131(1002), 084204.](https://mysteriesdept.com/sources/SRC0D8E6WF825PK/non-gray-month-long-brightening-of-kic-8462852-in-the)[doi](https://doi.org/10.1088/1538-3873/ab254f)cited 1 time here**SRC** 0D8E6WF825PK
1. 22.[arXiv:2609.02726 (September 2026). A Bayesian recurrence test on the dip families gives a Bayes factor of about 45 for recurrence at a period of 781.6 days with a width of 80 days. A dated, testable claim for the periodic reading.](https://mysteriesdept.com/sources/SRC0DDYDQXYHKF0/revisiting-orbital-recurrence-in-the-dimmings-of-boyajians)cited 1 time here**SRC** 0DDYDQXYHKF0
1. 23.[ApJ 853, 130. GALEX near-ultraviolet photometry 2011 versus 2012 shows a 3 per cent decrease coincident with the Kepler fade, with R_V = 5.0 +/- 0.9: a colour constraint on the secular dimming independent of Meng et al.](https://mysteriesdept.com/sources/SRC0DDYD8QX6P2X/the-galex-view-of-boyajians-star-kic-8462852)[doi](https://doi.org/10.3847/1538-4357/aaa413)cited 1 time here**SRC** 0DDYD8QX6P2X
1. 24.[ASAS-SN 2015-2017: fade of 6.3 +/- 1.4 mmag per year, more extreme than 99.4 per cent of 1,078 comparison stars; ASAS V 2006-2017 shows brightening 2006-07, dimming 2009-13 (15.8 +/- 1.5 mmag/yr) and brightening around 2014, so a straight line is a poor description. The modern-era reference for the fade's non-monotonic history.](https://mysteriesdept.com/sources/SRC0DDYCFP5PH7F/where-is-the-flux-going-the-long-term-photometric)[doi](https://doi.org/10.3847/1538-4357/aaa0c1)cited 1 time here**SRC** 0DDYCFP5PH7F
1. 25.[ApJL 854, L11. Cross-calibrates ASAS-SN, ASAS, Kepler, Gaia, SuperWASP and amateur photometry 2006-2017 to the millimagnitude level; the roughly 4 per cent year-long variations cannot be cyclic with a period under 10 years.](https://mysteriesdept.com/sources/SRC0DDYD8C3C84H/the-year-long-flux-variations-in-boyajians-star-are)[doi](https://doi.org/10.3847/2041-8213/aaab44)cited 1 time here**SRC** 0DDYD8C3C84H
1. 26.[Schaefer, B., Bentley, R., Boyajian, T. et al. 2018. The KIC 8462852 light curve from 2015.75 to 2018.18 shows a variable secular decline. Monthly Notices of the Royal Astronomical Society 481(2), 2235–2248.](https://mysteriesdept.com/sources/SRC0D8E6W7E2XQT/the-kic-8462852-light-curve-from-2015-75-to-2018-18-shows-a)[doi](https://doi.org/10.1093/mnras/sty1644)cited 2 times here**SRC** 0D8E6W7E2XQT
1. 27.[Schaefer's public rebuttal (with a follow-up post of 24 May 2016): Hippke's comparison stars mixed red and yellow plates and included flagged data, and crowded stars are merged by SExtractor on the coarse dnb plates; his own uncrowded, colour-matched check stars have a mean slope of -0.007 with rms 0.044 mag per century, making the fade 4 sigma. There is no separate journal rebuttal; v2 of arXiv:1601.03256 carries the same critique.](https://mysteriesdept.com/sources/SRC0DDYDRHV579S/bradley-schaefer-a-response-to-michael-hippke-centauri)cited 3 times here**SRC** 0DDYDRHV579S
1. 28.[arXiv:1605.02760 (preprint, May 2016). DASCH light curves of 644 F stars (337 Tycho-2 F3 IV/V in APASS B, 307 KIC analogues in g). The population's slope statistics are over-dispersed until a break at 1970 (the Menzel gap) is modelled; the target's full-series B slope of 0.129 +/- 0.026 mag per century splits into two flat segments and a jump; 11 of 644 stars still exceed 5 sigma after the split. Concludes that several apparent F-star fades are artefacts of the gap and that KIC 8462852 is consistent with constant flux.](https://mysteriesdept.com/sources/SRC0DDYCEJ03QA3/the-stability-of-f-star-brightness-on-century-timescales)cited 4 times here**SRC** 0DDYCEJ03QA3
1. 29.[Independent plate archive (Sonneberg Sky Patrol, 1934-1995): 861 pg and 397 pv magnitudes, differential against 39 colour-matched comparison stars. Combined slope -0.006 +/- 0.032 mag per century; rejects 0.164 at 4.9 sigma. Also Sternberg (Moscow) plates 1895-1995: -0.046 +/- 0.040. Key evidence against a real century fade and against a 1955-65 drop.](https://mysteriesdept.com/sources/SRC0DDYCDVVCM9Z/sonneberg-plate-photometry-for-boyajians-star-in-two)[doi](https://doi.org/10.3847/1538-4357/aa615d)cited 3 times here**SRC** 0DDYCDVVCM9Z
1. 30.[JAAVSO 46. Third plate archive: 835 Maria Mitchell Observatory plates, 8 APASS comparison stars. Slope +0.11 +/- 0.04 unbinned, +0.12 +/- 0.02 in 5-year bins; six of eight comparison stars flat within 0.04. Disagrees with Sonneberg at about 3 sigma.](https://mysteriesdept.com/sources/SRC0DDYCF5BWX7M/a-search-for-the-long-term-dimming-of-kic-8462852-on-maria)cited 3 times here**SRC** 0DDYCF5BWX7M
1. 31.[Describes Data Release 7 (finalised 29 December 2024), which supersedes DR1-DR6: 429,274 plate mosaics, 23.6 billion B magnitudes for 252 million sources calibrated to APASS DR8; typical light-curve rms about 0.15 mag. The release Schaefer and Hippke used in 2016 is no longer served, so DR7 is the only reproducible basis for the century-fade question. See also https://dasch.cfa.harvard.edu/dr7/ for the known-issues list, colour terms and the daschlab API.](https://mysteriesdept.com/sources/SRC0DDYCFZA4FXE/dasch-bringing-100-years-of-photographic-data-into-the-21st)cited 5 times here**SRC** 0DDYCFZA4FXE
1. 32.[PASP 125, 857. The DASCH photometric pipeline: defect and blend filtering, local calibration against similar-magnitude neighbours, rms about 0.1 mag, tested on the Kepler field. With Laycock et al. 2010 (AJ 140, 1062) and Grindlay et al. 2012 (IAU Symp. 285), the citation basis for any DASCH measurement.](https://mysteriesdept.com/sources/SRC0DDYCGKZAYSF/improved-photometry-for-the-dasch-pipeline)[doi](https://doi.org/10.1086/671760)**SRC** 0DDYCGKZAYSF
1. 33.[RNAAS 2, 16. Re-ranks the explanation families after the 2017 colour results; circumstellar dust favoured for the dips, with the fade's origin left open.](https://mysteriesdept.com/sources/SRC0DDYD97JZ9YW/a-reassessment-of-families-of-solutions-to-the-puzzle-of)[doi](https://doi.org/10.3847/2515-5172/aaa83e)cited 1 time here**SRC** 0DDYD97JZ9YW
1. 34.[MNRAS 473, 5286. Shows dips and the Kepler-era fade can share one exocomet population on an eccentric orbit; a 16 per cent century fade, if optically thin, must have ended before the 2010 WISE 12-micron measurement, and the transiting material lies between 0.05 and 0.6 au.](https://mysteriesdept.com/sources/SRC0DDYDA0EZAK2/modelling-the-kic8462852-light-curves-compatibility-of-the)[doi](https://doi.org/10.1093/mnras/stx2713)cited 1 time here**SRC** 0DDYDA0EZAK2
1. 35.[Metzger, B., Shen, K., Stone, N. 2017. Secular dimming of KIC 8462852 following its consumption of a planet. Monthly Notices of the Royal Astronomical Society 468(4), 4399–4407.](https://mysteriesdept.com/sources/SRC0D8E6YDR4ZK8/secular-dimming-of-kic-8462852-following-its-consumption-of)[doi](https://doi.org/10.1093/mnras/stx823)cited 3 times here**SRC** 0D8E6YDR4ZK8
1. 36.[MNRAS 489, 5119. An evaporating exomoon tidally detached after its planet's collision with the star feeds a dust disk; proposed to produce both the dips and the longer-term dimming.](https://mysteriesdept.com/sources/SRC0DDYDPJ50S5S/orphaned-exomoons-tidal-detachment-and-evaporation-following)[doi](https://doi.org/10.1093/mnras/stz2464)cited 1 time here**SRC** 0DDYDPJ50S5S
1. 37.[ApJL 842, L3. The one intrinsic-star model for the decadal dimming: storage of convective flux in the outer layers, with the dips' reddening read as a cooling of about 30 K rather than extinction.](https://mysteriesdept.com/sources/SRC0DDYD9PCG61B/an-explanation-of-the-missing-flux-from-boyajians-mysterious)[doi](https://doi.org/10.3847/2041-8213/aa740f)cited 1 time here**SRC** 0DDYD9PCG61B
1. 38.[Shestakova, L., Serebryanskiy, A., Demchenko, B. 2021. Infalling thermally destroyed bodies as a possible explanation for the KIC 8462852 phenomenon. Monthly Notices of the Royal Astronomical Society 501(4), 5468–5477.](https://mysteriesdept.com/sources/SRC0D8E6YXC4TYN/infalling-thermally-destroyed-bodies-as-a-possible)[doi](https://doi.org/10.1093/mnras/staa4023)cited 2 times here**SRC** 0D8E6YXC4TYN
1. 39.[ApJL 856, L8. Argued from early astrometry that the faint neighbour is not bound; superseded by the five-year Keck astrometry of Pearce et al. 2021, which finds it co-moving.](https://mysteriesdept.com/sources/SRC0DDYDQ4JP889/proper-motion-of-the-faint-star-near-kic-8462852-boyajians)[doi](https://doi.org/10.3847/2041-8213/aab492)cited 1 time here**SRC** 0DDYDQ4JP889
1. 40.[Pearce, L., Kraus, A., Dupuy, T. et al. 2021. Boyajian's Star B: The Co-moving Companion to KIC 8462852 A. The Astrophysical Journal 909(2), 216.](https://mysteriesdept.com/sources/SRC0D8E6Z5650DJ/boyajians-star-b-the-co-moving-companion-to-kic-8462852-a)[doi](https://doi.org/10.3847/1538-4357/abdd33)cited 6 times here**SRC** 0D8E6Z5650DJ
1. 41.[Young, S., Wyatt, M. 2023. The eccentric Kozai–Lidov mechanism as the cause of exocomet transits of KIC 8462852. Monthly Notices of the Royal Astronomical Society 527(3), 5244–5264.](https://mysteriesdept.com/sources/SRC0D8E6ZD025AJ/the-eccentric-kozailidov-mechanism-as-the-cause-of-exocomet)[doi](https://doi.org/10.1093/mnras/stad2963)cited 2 times here**SRC** 0D8E6ZD025AJ
1. 42.[Space Telescope Science Institute 2026. Mikulski Archive for Space Telescopes (MAST): Kepler, K2 and TESS light curves. MAST, STScI.](https://mysteriesdept.com/sources/SRC0D8E70VW54P8/mikulski-archive-for-space-telescopes-mast-kepler-k2-and)cited 8 times here**SRC** 0D8E70VW54P8
1. 43.[Harp, G., Richards, J., Shostak, S. et al. 2016. Radio SETI Observations of the Anomalous Star KIC 8462852. The Astrophysical Journal 825(2), 155.](https://mysteriesdept.com/sources/SRC0D8E6XY45ZP7/radio-seti-observations-of-the-anomalous-star-kic-8462852)[doi](https://doi.org/10.3847/0004-637x/825/2/155)cited 2 times here**SRC** 0D8E6XY45ZP7
1. 44.[Schuetz, M., Vakoch, D., Shostak, S. et al. 2016. Optical SETI Observations of the Anomalous Star KIC 8462852. The Astrophysical Journal Letters 825(1), L5.](https://mysteriesdept.com/sources/SRC0D8E6Y5Y5Y0H/optical-seti-observations-of-the-anomalous-star-kic-8462852)[doi](https://doi.org/10.3847/2041-8205/825/1/l5)cited 2 times here**SRC** 0D8E6Y5Y5Y0H
1. 45.[Schmidt, E. 2019. A Search for Analogs of KIC 8462852 (Boyajian's Star): A Proof of Concept and the First Candidates. The Astrophysical Journal Letters 880(1), L7.](https://mysteriesdept.com/sources/SRC0D8E6ZMT54K8/a-search-for-analogs-of-kic-8462852-boyajians-star-a-proof)[doi](https://doi.org/10.3847/2041-8213/ab2e77)cited 1 time here**SRC** 0D8E6ZMT54K8
1. 46.[Schmidt, E. 2021. A Search for Analogs of KIC 8462852 (Boyajian's Star): A Second List of Candidates. The Astronomical Journal 163(1), 10.](https://mysteriesdept.com/sources/SRC0D8E6ZWM07BF/a-search-for-analogs-of-kic-8462852-boyajians-star-a-second)[doi](https://doi.org/10.3847/1538-3881/ac3416)cited 1 time here**SRC** 0D8E6ZWM07BF

Last edited 30 Oct 2026