HD 191939 revisited: New and refined planet mass determinations, and a new planet in the habitable zone
Artikel i vetenskaplig tidskrift, 2023
HD 191939 (TOI-1339) is a nearby (d = 54 pc), bright (V = 9 mag), and inactive Sun-like star (G9 V) known to host a multi-planet transiting system. Ground-based spectroscopic observations confirmed the planetary nature of the three transiting sub-Neptunes (HD 191939 b, c, and d) originally detected by TESS and were used to measure the masses for planets b and c with 3Ï precision. These previous observations also reported the discovery of an additional Saturn-mass planet (HD 191939 e) and evidence for a further, very long-period companion (HD 191939 f). Here, we report the discovery of a new non-transiting planet in the system and a refined mass determination of HD 191939 d. The new planet, HD 191939 g, has a minimum mass of 13.5±2.0 M- and a period of about 280 days. This period places the planet within the conservative habitable zone of the host star, and near a 1:3 resonance with HD 191939 e. The compilation of 362 radial velocity measurements with a baseline of 677 days from four different high-resolution spectrographs also allowed us to refine the properties of the previously known planets, including a 4.6Ï mass determination for planet d, for which only a 2Ï upper limit had been set until now. We confirm the previously suspected low density of HD 191939 d, which makes it an attractive target for attempting atmospheric characterisation. Overall, the planetary system consists of three sub-Neptunes interior to a Saturn-mass and a Uranus-mass planet plus a high-mass long-period companion. This particular configuration has no counterpart in the literature and makes HD 191939 an exceptional multi-planet transiting system with an unusual planet demographic worthy of future observation.
Stars: individual: HD 191939
Planets and satellites: individual: HD 191939 g
Techniques: photometric
Planets and satellites: individual: HD 191939 d
Techniques: radial velocities
Författare
J. Orell-Miquel
Instituto de Astrofísica de Canarias
Universidad de la Laguna
G. Nowak
Universidad de la Laguna
Instituto de Astrofísica de Canarias
F. Murgas
Universidad de la Laguna
Instituto de Astrofísica de Canarias
E. Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
Giuseppe Morello
Instituto de Astrofísica de Canarias
Universidad de la Laguna
R. Luque
University of Chicago
Instituto de Astrofisica de Andalucía (IAA)
M. Badenas-Agusti
Massachusetts Institute of Technology (MIT)
I. Ribas
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
Marina Lafarga
The University of Warwick
Néstor Espinoza
Max-Planck-Gesellschaft
J. C. Morales
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
M. Zechmeister
Georg-August-Universität Göttingen
A. Alqasim
University College London (UCL)
W. D. Cochran
The University of Texas at Austin
Center for Planetary Systems Habitability
D. Gandolfi
Universita degli Studi di Torino
E. Goffo
Universita degli Studi di Torino
Thüringer Landessternwarte Tautenburg
Petr Kabath
Czech Academy of Sciences
Judith Korth
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
K. W.F. Lam
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Livingston
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
Alexandra Muresan
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Carina Persson
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Vincent Van Eylen
University College London (UCL)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 669 A40Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två rymdteleskop (fas 2)
Rymdstyrelsen (177/19), 2020-01-01 -- 2022-12-31.
Rymdstyrelsen (65/19), 2020-01-01 -- 2022-12-31.
Ämneskategorier
Subatomär fysik
Astronomi, astrofysik och kosmologi
Annan fysik
DOI
10.1051/0004-6361/202244120