# Rappaport 2019: The Random Transiter – EPIC 249706694/HD 139139 > S. Rappaport, A. Vanderburg, M. H. Kristiansen et al., 2019. 45 records on Mysteries Department cite it. The primary description of the dips, the two… Source: https://mysteriesdept.com/sources/SRC0D79RTR64N25/the-random-transiter-epic-249706694-hd-139139 Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Sources](https://mysteriesdept.com/sources)[HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter)Rappaport 2019 **0** # The Random Transiter – EPIC 249706694/HD 139139 S. Rappaport, A. Vanderburg, M. H. Kristiansen et al., 2019. _Monthly Notices of the Royal Astronomical Society 488(2), 2455–2465_. The discovery paper. In K2 Campaign 15, the star shows 28 transit-like dips in 87 days, almost all 200 ± 80 ppm deep and 1 to 7 hours long, at times that look random; no more than four can belong to one periodic sequence. Data-quality tests (rolling bands, centroids, cross-talk, bad pixels) find no instrumental cause. A fainter K-type star 3.3 arcseconds away, probably bound, shares the aperture. Spectra from TRES and McDonald show no large radial-velocity changes. Planetary, binary, asteroid, dipper and starspot scenarios are examined and none is satisfactory. **HD 139139, the "Random Transiter"** ArticleCopy of **[K2 Campaign 15 light curve and pixel data of EPIC 249706694](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/artifacts/ART0D79S9CY4YRG/k2-campaign-15-light-curve-and-pixel-data-of-epic-249706694)** doi: **[10.1093/mnras/stz1772](https://doi.org/10.1093/mnras/stz1772)** Checked against the original0 ## What it's used for here The primary description of the dips, the two stars and every tested explanation. ## Cited by on this site 45 records [A disintegrating ultra-short-period planet whose dust tail is only sometimes thick enough to be seen.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S3HE78QH/a-disintegrating-ultra-short-period-planet-whose-dust-tail) Answer ANS [A planet in a close binary (S-type, eccentric and precessing) or around a binary (P-type), whose transits are…](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S2T07JV5/a-planet-in-a-close-binary-s-type-eccentric-and-precessing) Answer ANS [Dipper-star behaviour of the kind seen in young stars with disks, on star B and diluted by star A.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S4RG7PHD/dipper-star-behaviour-of-the-kind-seen-in-young-stars-with) Answer ANS [Many dust-emitting asteroids or planetesimals on different orbits.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S48W44R1/many-dust-emitting-asteroids-or-planetesimals-on-different) Answer ANS [Several planets, possibly with large transit-timing variations, around one or both stars.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S2AC0ZDR/several-planets-possibly-with-large-transit-timing) Answer ANS [Short-lived dark spots that appear within half an hour, last a few hours and vanish.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S5FY6FRB/short-lived-dark-spots-that-appear-within-half-an-hour-last) Answer ANS [Star A, HD 139139, with occulters about twice Earth's radius.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S67C1PGW/star-a-hd-139139-with-occulters-about-twice-earths-radius) Answer ANS [Star B, the fainter K star, with occulters of one to two Jupiter radii or deep intrinsic dips.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S6F66ZK9/star-b-the-fainter-k-star-with-occulters-of-one-to-two) Answer ANS [The dipping is a lasting property of the system and recurs in any long enough observation.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S6YT4CKQ/the-dipping-is-a-lasting-property-of-the-system-and-recurs) Answer ANS [The dipping was an episode in 2017 that may not recur.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S76M6NAD/the-dipping-was-an-episode-in-2017-that-may-not-recur) Answer ANS [The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S1JY7DXT/the-dips-are-an-undiagnosed-instrumental-or-data-processing) Answer ANS [The dips are astrophysical, on star A or star B.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/answers/ANS0D79S0VG5ZJW/the-dips-are-astrophysical-on-star-a-or-star-b) Answer ANS [K2 Campaign 15 light curve and pixel data of EPIC 249706694](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/artifacts/ART0D79S9CY4YRG/k2-campaign-15-light-curve-and-pixel-data-of-epic-249706694) ART [TRES and McDonald spectra of HD 139139](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/artifacts/ART0D79SAC665R1/tres-and-mcdonald-spectra-of-hd-139139) ART [K2 Campaign 15 light curve and pixel data of EPIC 249706694: document](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/copies/CPY0D79SA4C0DZS/k2-campaign-15-light-curve-and-pixel-data-of-epic-249706694) CPY [TRES and McDonald spectra of HD 139139: document](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/copies/CPY0D79SAM07HH4/tres-and-mcdonald-spectra-of-hd-139139-document) CPY [Table of the 28 transit-like events (times, durations, depths)](https://mysteriesdept.com/datasets/DAT0D79S85W24A0/table-of-the-28-transit-like-events-times-durations-depths) Dataset DAT [Almost all dips have similar depths, which many independent bodies are unlikely to produce.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S4GP13BD/almost-all-dips-have-similar-depths-which-many-independent) Evidence EVD [K2 pixels can't separate real dimming from a glitch in the saturated bleed column](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0DD2G5TEHHJB/k2-pixels-cant-separate-real-dimming-from-a-glitch-in-the) Evidence EVD [No more than four dips can belong to one periodic sequence; models with huge timing variations fit at most…](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S2J63P9P/no-more-than-four-dips-can-belong-to-one-periodic-sequence) Evidence EVD [Only 7 per cent of more than 400 transits would show; simulations put this near the limit of detectability.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S3S853YH/only-7-per-cent-of-more-than-400-transits-would-show) Evidence EVD [Radial velocities exclude stellar and brown-dwarf companions to star A on orbits under about 10 days; no…](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S39M6XRD/radial-velocities-exclude-stellar-and-brown-dwarf-companions) Evidence EVD [Simulations of an eccentric S-type planet always left a detectable periodicity.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S31T6VDJ/simulations-of-an-eccentric-s-type-planet-always-left-a) Evidence EVD [Star B's possible infrared excess would be hidden by the dilution.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S5842FX3/star-bs-possible-infrared-excess-would-be-hidden-by-the) Evidence EVD [TESS Sector 91 is too insensitive to test whether the K2 dipping continues](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0DD2FTEBQ37T/tess-sector-91-is-too-insensitive-to-test-whether-the-k2) Evidence EVD [Ten known dippers diluted by a factor of 15 do not resemble this light curve.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S50A670A/ten-known-dippers-diluted-by-a-factor-of-15-do-not-resemble) Evidence EVD [Tests for rolling bands, centroid shifts, cross-talk and bad pixels find nothing; neighbouring stars do not…](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S13A3E7F/tests-for-rolling-bands-centroid-shifts-cross-talk-and-bad) Evidence EVD [The K2 dips stand out in two independent reductions under a symmetric null](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0DD2G4SX1J8X/the-k2-dips-stand-out-in-two-independent-reductions-under-a) Evidence EVD [The K2 pixels and the PRF can't tell whether star A or star B dips](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0DD2G64S1N9H/the-k2-pixels-and-the-prf-cant-tell-whether-star-a-or-star-b) Evidence EVD [The authors find no physical law violated and note such events could have gone unnoticed in other stars.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S5QR6MV6/the-authors-find-no-physical-law-violated-and-note-such) Evidence EVD [The authors state that they cannot formally exclude an anomaly in a group of pixels.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S1TR5WKM/the-authors-state-that-they-cannot-formally-exclude-an) Evidence EVD [The average dip profile shows none of the asymmetry expected from a dust tail.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S41276X2/the-average-dip-profile-shows-none-of-the-asymmetry-expected) Evidence EVD [The dips don't behave like a single telegraph pixel or follow the spacecraft's motion](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0DD2G555HMN8/the-dips-dont-behave-like-a-single-telegraph-pixel-or-follow) Evidence EVD [The dips were first seen in the Kepler pipeline light curve and analysed in the independent K2SFF reduction.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S1B46GYE/the-dips-were-first-seen-in-the-kepler-pipeline-light-curve) Evidence EVD [K2 Campaign 15 records 28 dips in 87 days](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/events/EVT0D79RYN60155/k2-campaign-15-records-28-dips-in-87-days) EVT [Rappaport and colleagues publish "The Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/events/EVT0D79RZ4T3P3H/rappaport-and-colleagues-publish-the-random-transiter) EVT [TRES and McDonald spectra rule out large radial-velocity variations](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/events/EVT0D79RYX06VBQ/tres-and-mcdonald-spectra-rule-out-large-radial-velocity) EVT [Saul Rappaport](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/people/FIG0D79RXNY7H6E/saul-rappaport) FIG [K2 pixel forensics for a saturated star](https://mysteriesdept.com/methods/MTH0DD2FKPWB8AP/k2-pixel-forensics-for-a-saturated-star) Method MTH [Single-event dip search with injection-recovery and fair nulls](https://mysteriesdept.com/methods/MTH0DD2FEM3PXJB/single-event-dip-search-with-injection-recovery-and-fair) Method MTH [HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter) The mystery article MYS [Are the 28 dips real changes in starlight, or an instrumental effect?](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/questions/QST0D79RZW80KRQ/are-the-28-dips-real-changes-in-starlight-or-an-instrumental) Question QST [Do the dips still occur?](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/questions/QST0D79S0KP69RV/do-the-dips-still-occur) Question QST [If the dips are real, what causes them?](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/questions/QST0D79S04202NJ/if-the-dips-are-real-what-causes-them) Question QST [Which of the two stars dips?](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/questions/QST0D79S0BW0FXC/which-of-the-two-stars-dips) Question QST ## Cite it ``` Rappaport, S., Vanderburg, A., Kristiansen, M. H., Omohundro, M. R., Schwengeler, H. M., Terentev, I. A., & et al. (2019). The Random Transiter – EPIC 249706694/HD 139139. Monthly Notices of the Royal Astronomical Society 488(2), 2455–2465. https://doi.org/10.1093/mnras/stz1772 ``` [Read it free at doi.org](https://doi.org/10.1093/mnras/stz1772) Key **SRC** 0D79RTR64N25 Kind Journal article Rights The publisher's Kept 27 Oct 2026, for editors Checked Against the published article Added by [apollo](https://mysteriesdept.com/u/apollo) The record Bibliographic records are CC0. Take this one as CSL-JSON, BibTeX or RIS. [CSL-JSON](https://mysteriesdept.com/sources/SRC0D79RTR64N25/the-random-transiter-epic-249706694-hd-139139/csl.json)