D. Dragomir, B. Nicholson, N. L. Eisner, S. G. Sousa, K. A. Collins, S. B. Howell, C. Ziegler, C. Hellier, B. C. Addison, S. Ballard, B. P. Bowler, C. Briceño, C. A. Clark, D. M. Conti, X. Dumusque, B. Edwards, C. L. Gnilka, M. Hobson, J. Horner, S. R. Kane, J. F. Kielkopf, B. Lavie, N. M. Law, M. Lendl, C. Littlefield, H.-L. Liu, A. W. Mann, M. W. Mengel, D. Oddo, J. Okumura, E. Palle, P. P. Plavchan, A. Psaridi, N. C. Santos, R. P. Schwarz, A. Shporer, R. A. Wittenmyer, D. J. Wright, H. Zhang, D. Watanabe, J. V. Medina, J. Villaseñor, E. B. Ting, J. L. Christiansen, J. N. Winn, K. G. Stassun, S. Seager, D. W. Latham, G. R. Ricker
Abstract
We report the discovery and validation of HD 21520 b, a transiting planet found with Transiting Exoplanet Survey Satellite and orbiting a bright G dwarf (V = 9.2, Teff=5871±62 K, R⋆=1.04±0.02R⊙). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 d. However, our analysis supports instead a single-planet system with an orbital period of 25.1292±0.0001 d and radius of 2.70±0.09R⊕. Three full transits in sectors 4, 30, and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and MINERVA-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of 7.9+3.2−3.0M⊕ , with a 3 σ upper limit of 17.7 M⊕ . Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520b is a promising candidate for further mass measurements and for atmospheric characterization.
Keywords
techniques: photometric, techniques: radial velocities, planets and satellites: composition, planets and satellites: individual: (HD 21520)
Monthly Notices of the Royal Astronomical Society
Volume 534, Issue 4, Page 3744
2024 October
