Mass determinations of the three mini-Neptunes transiting TOI-125

Nielsen, LD; Gandolfi, D.; Armstrong, DJ; Jenkins, JS; Fridlund, M; Santos, NC; Dai, F; Adibekyan, V; Luque, R; Steffen, JH; Esposito, M; Meru, F; Sabotta, S; Bolmont, E; Kossakowski, D; et. al.

Keywords: planets and satellites: detection, Planets and satellites: individual: (TOI-125, TIC 52368076)

Abstract

The Transiting Exoplanet Survey Satellite, TESS, is currently carrying out an all-sky search for small planets transiting bright stars. In the first year of the TESS survey, a steady progress was made in achieving the mission's primary science goal of establishing bulk densities for 50 planets smaller than Neptune. During that year, the TESS's observations were focused on the southern ecliptic hemisphere, resulting in the discovery of three mini-Neptunes orbiting the star T01-125, a V = 11,0 KO dwarf. We present intensive HARPS radial velocity observations, yielding precise mass measurements for TO1-125b, TOI-125c, and TOI-125d. TOI-125b has an orbital period of 4,65 d, a radius of 2,726 + 0,075 RE, a mass of 9,50 0,88 ME, and is near the 2:1 mean motion resonance with TOI-125c at 9.15 d. TOI-125c has a similar radius of 2,759 0.10 RE and a mass of 6,63 + 0,99 ME, being the puffiest of the three planets. T01-125d has an orbital period of 19,98 d and a radius of 2.93 + 0,17 RE and mass 13,6 1,2 ME, For T01-125b and d, we find unusual high eccentricities of 0.19 0.04 and 0.17+(c):(!,(, respectively. Our analysis also provides upper mass limits for the two low-SNR planet candidates in the system; for T01-125.04 (Rp = 1.36 RE, P = 0.53 d), we find a 2a upper mass limit of 1.6 ME, whereas T01-125.05 (RP = 4.2-'2E44 RE, P = 13.28 d) is unlikely a viable planet candidate with an upper mass limit of 2.7 ME. We discuss the internal structure of the three confirmed planets, as well as dynamical stability and system architecture for this intriguing exoplanet system.

Más información

Título según WOS: Mass determinations of the three mini-Neptunes transiting TOI-125
Título de la Revista: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volumen: 492
Número: 4
Editorial: OXFORD UNIV PRESS
Fecha de publicación: 2020
Página de inicio: 5399
Página final: 5412
Idioma: English
DOI:

10.1093/mnras/staa197

Notas: ISI