HD219666b: A hot-Neptune from TESS Sector 1
Abstract
We report on the confirmation and mass determination of a transiting planet orbiting the old and inactive G7 dwarf star HD219666 (Mstar = 0.92 +/- 0.03 MSun, Rstar = 1.03 +/- 0.03 RSun, tau_star = 10 +/- 2 Gyr). With a mass of Mb = 16.6 +/- 1.3 MEarth, a radius of Rb = 4.71 +/- 0.17 REarth, and an orbital period of P ~ 6 days, HD219666b is a new member of a rare class of exoplanets: the hot-Neptunes. The Transiting Exoplanet Survey Satellite (TESS) observed HD219666 (also known as TOI-118) in its Sector 1 and the light curve shows four transit-like events, equally spaced in time. We confirmed the planetary nature of the candidate by gathering precise radial-velocity measurements with [email protected]. We used the co-added HARPS spectrum to derive the host star fundamental parameters (Teff = 5527 +/- 65 K, log g = 4.40 +/- 0.11 (cgs), [Fe/H]= 0.04 +/- 0.04 dex, log R'HK = -5.07 +/- 0.03), as well as the abundances of many volatile and refractory elements. The host star brightness (V = 9.9) makes it suitable for further characterisation by means of in-transit spectroscopy. The determination of the planet orbital obliquity, along with the atmospheric metal-to-hydrogen content and thermal structure could provide us with important clues on the formation mechanisms of this class of objects.
Cite
@article{arxiv.1812.05881,
title = {HD219666b: A hot-Neptune from TESS Sector 1},
author = {M. Esposito and D. J. Armstrong and D. Gandolfi and V. Adibekyan and M. Fridlund and N. C. Santos and J. H. Livingston and E. Delgado Mena and L. Fossati and J. Lillo-Box and O. Barragán and D. Barrado and P. E. Cubillos and B. Cooke and A. B. Justesen and F. Meru and R. F. Díaz and F. Dai and L. D. Nielsen and C. M. Persson and P. J. Wheatley and A. P. Hatzes and V. Van Eylen and M. M. Musso and R. Alonso and P. Beck and S. C. C. Barros and D. Bayliss and A. S. Bonomo and F. Bouchy and D. J. A. Brown and E. Bryant and J. Cabrera and W. D. Cochran and S. Csizmadia and H. Deeg and O. Demangeon and M. Deleuil and X. Dumusque and P. Eigmüller and M. Endl and A. Erikson and F. Faedi and P. Figueira and A. Fukui and S. Grziwa and E. W. Guenther and D. Hidalgo and M. Hjorth and T. Hirano and S. Hojjatpanah and E. Knudstrup and J. Korth and K. W. F. Lam and J. de Leon and M. N. Lund and R. Luque and S. Mathur and P. Montañés Rodríguez and N. Narita and D. Nespral and P. Niraula and G. Nowak and H. P. Osborn and E. Pallé and M. Pätzold and D. Pollacco and J. Prieto-Arranz and H. Rauer and S. Redfield and I. Ribas and S. G. Sousa and A. M. S. Smith and M. Tala-Pinto and S. Udry and J. N. Winn},
journal= {arXiv preprint arXiv:1812.05881},
year = {2019}
}
Comments
Accepted for publication in A&A