TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis

© ESO 2020. Context. We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered...

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Format: Article
Language:English
Published: EDP Sciences 2021
Online Access:https://hdl.handle.net/1721.1/134563
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collection MIT
description © ESO 2020. Context. We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered than expected from planet formation models. TOI-519 is a valuable addition to this group of unlikely systems, and it adds towards our understanding of the boundaries of planet formation. Aims. We set out to determine the nature of the Transiting Exoplanet Survey Satellite (TESS) object of interest TOI-519 b. Methods. Our analysis uses a SPOC-pipeline TESS light curve from Sector 7, multicolour transit photometry observed with MuSCAT2 and MuSCAT, and transit photometry observed with the LCOGT telescopes. We estimated the radius of the transiting object using multicolour transit modelling, and we set upper limits for its mass, effective temperature, and Bond albedo using a phase curve model that includes Doppler boosting, ellipsoidal variations, thermal emission, and reflected light components. Results. TOI-519 b is a substellar object with a radius posterior median of 1.07 RJup and 5th and 95th percentiles of 0.66 and 1.20 RJup, respectively, where most of the uncertainty comes from the uncertainty in the stellar radius. The phase curve analysis sets an upper effective temperature limit of 1800 K, an upper Bond albedo limit of 0.49, and a companion mass upper limit of 14 MJup. The companion radius estimate combined with the Teff and mass limits suggests that the companion is more likely a planet than a brown dwarf, but a brown-dwarf scenario is a priori more likely given the lack of known massive planets in ≈ 1 day orbits around M dwarfs with Teff < 3800 K, and given the existence of some (but few) brown dwarfs.
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spelling mit-1721.1/1345632021-10-28T04:10:07Z TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis © ESO 2020. Context. We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered than expected from planet formation models. TOI-519 is a valuable addition to this group of unlikely systems, and it adds towards our understanding of the boundaries of planet formation. Aims. We set out to determine the nature of the Transiting Exoplanet Survey Satellite (TESS) object of interest TOI-519 b. Methods. Our analysis uses a SPOC-pipeline TESS light curve from Sector 7, multicolour transit photometry observed with MuSCAT2 and MuSCAT, and transit photometry observed with the LCOGT telescopes. We estimated the radius of the transiting object using multicolour transit modelling, and we set upper limits for its mass, effective temperature, and Bond albedo using a phase curve model that includes Doppler boosting, ellipsoidal variations, thermal emission, and reflected light components. Results. TOI-519 b is a substellar object with a radius posterior median of 1.07 RJup and 5th and 95th percentiles of 0.66 and 1.20 RJup, respectively, where most of the uncertainty comes from the uncertainty in the stellar radius. The phase curve analysis sets an upper effective temperature limit of 1800 K, an upper Bond albedo limit of 0.49, and a companion mass upper limit of 14 MJup. The companion radius estimate combined with the Teff and mass limits suggests that the companion is more likely a planet than a brown dwarf, but a brown-dwarf scenario is a priori more likely given the lack of known massive planets in ≈ 1 day orbits around M dwarfs with Teff < 3800 K, and given the existence of some (but few) brown dwarfs. 2021-10-27T20:05:36Z 2021-10-27T20:05:36Z 2021 2021-09-28T17:18:50Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/134563 en 10.1051/0004-6361/202038934 Astronomy and Astrophysics Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf EDP Sciences EDP Sciences
spellingShingle TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title_full TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title_fullStr TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title_full_unstemmed TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title_short TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
title_sort toi 519 b a short period substellar object around an m dwarf validated using multicolour photometry and phase curve analysis
url https://hdl.handle.net/1721.1/134563