GJ 1252 b : a 1.2 R⊕ planet transiting an M-dwarf at 20.4 pc

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.

Citation

Shporer , A , Collins , K A , Astudillo-Defru , N , Irwin , J , Bonfils , X , Collins , K I , Matthews , E , Winters , J G , Anderson , D R , Armstrong , J D , Charbonneau , D , Cloutier , R , Daylan , T , Gan , T , Günther , M N , Hellier , C , Horne , K , Huang , C X , Jensen , E L N , Kielkopf , J , Palle , E , Sefako , R , Stassun , K G , Tan , T-G , Vanderburg , A , Ricker , G R , Latham , D W , Vanderspek , R , Seager , S , Winn , J N , Jenkins , J M , Colon , K , Dressing , C D , Lépine , S , Muirhead , P S , Rose , M E , Twicken , J D & Villasenor , J N 2020 , ' GJ 1252 b : a 1.2 R ⊕ planet transiting an M-dwarf at 20.4 pc ' , Astrophysical Journal , vol. 890 , no. 1 . https://doi.org/10.3847/2041-8213/ab7020

Publication

Astrophysical Journal

Status

Peer reviewed

DOI

https://doi.org/10.3847/2041-8213/ab7020

ISSN

0004-637X

Type

Journal article

Rights

Copyright © 2020 American Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.3847/2041-8213/ab7020

Description

Funding: UK STFC grant ST/R000824/1 (K.H.).

Collections

University of St Andrews Research

URI

http://hdl.handle.net/10023/19377

St Andrews Research Repository