HD 20329b : An ultra-short-period planet around a solar-type star found by TESS
Summary, in English
Context. Ultra-short-period (USP) planets are defined as
planets with orbital periods shorter than one day. This type of planets
is rare, highly irradiated, and interesting because their formation
history is unknown.
Aims. We aim to obtain precise mass and radius measurements to
confirm the planetary nature of a USP candidate found by the Transiting
Exoplanet Survey Satellite (TESS). These parameters can provide
insights into the bulk composition of the planet candidate and help to
place constraints on its formation history.
Methods. We used TESS light curves and HARPS-N spectrograph
radial velocity measurements to establish the physical properties of the
transiting exoplanet candidate found around the star HD 20329
(TOI-4524). We performed a joint fit of the light curves and radial
velocity time series to measure the mass, radius, and orbital parameters
of the candidate.
Results. We confirm and characterize HD 20329b, a USP planet transiting a solar-type star. The host star (HD 20329, V = 8.74 mag, J = 7.5 mag) is characterized by its G5 spectral type with M* = 0.90 ± 0.05 M⊙, R* = 1.13 ± 0.02 R⊙, and Teff = 5596 ± 50 K; it is located at a distance d
= 63.68 ± 0.29 pc. By jointly fitting the available TESS transit light
curves and follow-up radial velocity measurements, we find an orbital
period of 0.9261 ± (0.5 × 10−4) days, a planetary radius of 1.72 ± 0.07 R⊗, and a mass of 7.42 ± 1.09 M⊗, implying a mean density of ρp = 8.06 ± 1.53 g cm−3. HD 20329b joins the ~30 currently known USP planets with radius and Doppler mass measurements.
- Astronomy, Astrophysics and Cosmology
- Planets and satellites: detection
- Techniques: photometric
- Techniques: radial velocities
- ISSN: 0004-6361