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GJ 1252 b: A 1.2 R? Planet Transiting an M3 Dwarf at 20.4 pc


GJ 1252 b: A 1.2 R? Planet Transiting an M3 Dwarf at 20.4 pc Thumbnail



We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 , 0.391 ± 0.020 ) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal as originating from an eclipsing stellar binary. Precise Doppler monitoring also leads to a tentative mass measurement of 2.09 ± 0.56 M ?. The host star proximity, brightness (V = 12.19 mag, K = 7.92 mag), low stellar activity, and the system’s short orbital period make this planet an attractive target for detailed characterization, including precise mass measurement, looking for other objects in the system, and planet atmosphere characterization.

Acceptance Date Jan 25, 2020
Publication Date Feb 10, 2020
Journal The Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Keywords Exoplanet astronomy, M dwarf stars, Exoplanets
Publisher URL


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