Pontificia Universidad Católica de Chile Pontificia Universidad Católica de Chile
Brahm R., Espinoza N., Jordan A., Henning T., Sarkis P., Jones M.I., Diaz M.R., Jenkins J.S., Vanzi L., Zapata A., Petrovich C., Kossakowski D., Rabus M., Rojas F., Torres P. (2019)

HD 1397b: A Transiting Warm Giant Planet Orbiting A V = 7.8 mag Subgiant Star Discovered by TESS

Revista : Astronomical Journal
Volumen : 158
Número : 1
Páginas : 45
Tipo de publicación : ISI Ir a publicación


We report the discovery of a transiting planet first identified as a candidate in Sector 1 of the Transiting Exoplanet Survey Satellite (TESS), and then confirmed with precision radial velocities. HD 1397b has a mass of {M}{{P}} ={0.367}-0.023+0.022 {M}{{J}}, a radius of {R}{{P}}={1.023}-0.013+0.013 {R}{{J}}, and orbits its bright host star (V = 7.8 mag) with an orbital period of 11.5366+/- 0.0003 d on a moderately eccentric orbit (e={0.216}-0.026+0.027). With a mass of {M}star ={1.257}-0.029+0.029 {M}☉ , a radius of {R}star ={2.341}-0.019+0.022 {R}☉ , and an age of 4.46+/- 0.25 Gyr, the solar-metallicity host star has already departed from the main sequence. We find evidence in the radial velocity measurements of a secondary signal with a longer period. We attribute it to the rotational modulation of stellar activity, but a long-term radial velocity monitoring would be necessary to discard if this signal is produced by a second planet in the system. The HD 1397 system is among the brightest ones currently known to host a transiting planet, which will make it possible to perform detailed follow-up observations in order to characterize the properties of giant planets orbiting evolved stars.