# Light curve · Concept > A star's brightness plotted against time. Source: https://mysteriesdept.com/concepts/CPT0DECW02VSSXN/light-curve Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Concepts](https://mysteriesdept.com/concepts)Light curve Concept · astronomy · in 3 mysteries # Light curve A star's brightness plotted against time. [HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter)[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua) The record of how bright an object was at each moment of observation. Its shape, depth, timing and colour dependence are what every account of a dimming star has to reproduce: a planet gives a flat-bottomed dip at fixed intervals, dust a ragged one that is deeper in blue light. The arguments over Tabby's star are arguments about its light curve. ## Where it comes up **[HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter)** Finds transit-like dips of 0.75–8 hours in a light curve, measures how many K2-like dips the data could have caught, and calibrates false alarms on the same data. [Single-event dip search with injection-recovery and fair nulls](https://mysteriesdept.com/methods/MTH0DD2FEM3PXJB/single-event-dip-search-with-injection-recovery-and-fair)[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)[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)[TESS Sector 91 full-frame-image light curves at the position of HD 139139 (2025)](https://mysteriesdept.com/datasets/DAT0D79S7Y20VHM/tess-sector-91-full-frame-image-light-curves-at-the-position)[K2 Campaign 15 light curves of EPIC 249706694 (pipeline, K2SFF and EVEREST)](https://mysteriesdept.com/datasets/DAT0D79S7P81J3J/k2-campaign-15-light-curves-of-epic-249706694-pipeline-k2sff) **[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)** Joins DR7's per-exposure colour term to a star's light curve, classes plates by DASCH's colour-term bands, and asks whether a long-term offset survives on good-blue plates alone and whether residuals track the colour… [Colour-term stratification of a DASCH DR7 long-term offset](https://mysteriesdept.com/methods/MTH0DEC0S4G0XB7/colour-term-stratification-of-a-dasch-dr7-long-term-offset)[Observer-offset ensemble reduction of the AAVSO record](https://mysteriesdept.com/methods/MTH0DED7CM4S3AY/observer-offset-ensemble-reduction-of-the-aavso-record)[Sliding-box dip search with injection-recovery for TESS light curves](https://mysteriesdept.com/methods/MTH0DDYEH1HVCN2/sliding-box-dip-search-with-injection-recovery-for-tess)[Matched-comparison century-slope test for DASCH light curves](https://mysteriesdept.com/methods/MTH0DDYEGKBWKWV/matched-comparison-century-slope-test-for-dasch-light-curves)[ASAS-SN image-subtraction reconciliation: fade slopes, catalogue comparison, camera tie-in and depression check](https://mysteriesdept.com/methods/MTH0DEEB7M73CED/asas-sn-image-subtraction-reconciliation-fade-slopes)[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) **[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua)** [The light curve shows no secular change in spin, which is in tension with how outgassing comets spin up.](https://mysteriesdept.com/mysteries/oumuamua/evidence/EVD0CSKC2B22PP3/the-light-curve-shows-no-secular-change-in-spin-which-is-in)[The light curve and lateral motion are unlikely for a sail.](https://mysteriesdept.com/mysteries/oumuamua/evidence/EVD0CSKCNM832AG/the-light-curve-and-lateral-motion-are-unlikely-for-a-sail) ## Methods that use it 6 [Single-event dip search with injection-recovery and fair nulls](https://mysteriesdept.com/methods/MTH0DD2FEM3PXJB/single-event-dip-search-with-injection-recovery-and-fair) HD 139139, the "Random Transiter" MTH [Colour-term stratification of a DASCH DR7 long-term offset](https://mysteriesdept.com/methods/MTH0DEC0S4G0XB7/colour-term-stratification-of-a-dasch-dr7-long-term-offset) Tabby's star (KIC 8462852) MTH [Observer-offset ensemble reduction of the AAVSO record](https://mysteriesdept.com/methods/MTH0DED7CM4S3AY/observer-offset-ensemble-reduction-of-the-aavso-record) Tabby's star (KIC 8462852) MTH [Sliding-box dip search with injection-recovery for TESS light curves](https://mysteriesdept.com/methods/MTH0DDYEH1HVCN2/sliding-box-dip-search-with-injection-recovery-for-tess) Tabby's star (KIC 8462852) MTH [Matched-comparison century-slope test for DASCH light curves](https://mysteriesdept.com/methods/MTH0DDYEGKBWKWV/matched-comparison-century-slope-test-for-dasch-light-curves) Tabby's star (KIC 8462852) MTH [ASAS-SN image-subtraction reconciliation: fade slopes, catalogue comparison, camera tie-in and depression check](https://mysteriesdept.com/methods/MTH0DEEB7M73CED/asas-sn-image-subtraction-reconciliation-fade-slopes) Tabby's star (KIC 8462852) MTH ## Cite it ``` Mysteries Department. (2026). Light curve [Concept CPT0DECW02VSSXN]. https://mysteriesdept.com/r/CPT0DECW02VSSXN ``` Key **CPT** 0DECW02VSSXN Record Concept Field Astronomy Related [Transit photometry](https://mysteriesdept.com/concepts/CPT0DECW02PHXR7/transit-photometry) Version 2 Added by [apollo](https://mysteriesdept.com/u/apollo) [ Wikidata](https://www.wikidata.org/wiki/Q1138738) **How this page is made.** The definition is the site's, in its own words. “Where it comes up” is read from the answers, methods and evidence that name the concept. Related concepts [Transit photometry](https://mysteriesdept.com/concepts/CPT0DECW02PHXR7/transit-photometry) The record Every record is open data. Take this one as JSON, with its links and its history. [JSON](https://mysteriesdept.com/api/v1/records/CPT0DECW02VSSXN)