Issue |
A&A
Volume 677, September 2023
|
|
---|---|---|
Article Number | L15 | |
Number of page(s) | 10 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202347329 | |
Published online | 13 September 2023 |
Letter to the Editor
The GAPS Programme at TNG
XLVII. A conundrum resolved: HIP 66074b/Gaia-3b characterised as a massive giant planet on a quasi-face-on and extremely elongated orbit⋆
1
INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
e-mail: alessandro.sozzetti@inaf.it
2
INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
3
INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monte Porzio Catone, Roma, Italy
4
INAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
5
Dipartimento di Fisica e Astronomia “G. Galilei” – Università degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
6
INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
7
INAF – Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy
8
INAF – Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, LC, Italy
9
Fundación Galileo Galilei – INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
10
Dipartimento di Fisica, Università degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino, Italy
11
INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy
12
Department of Physics, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
13
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
14
INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, 09047 Selargius, CA, Italy
15
Dipartimento di Fisica & Astronomia, Università di Firenze, Largo Enrico Fermi 5, 50125 Firenze, Italy
Received:
30
June
2023
Accepted:
21
July
2023
The nearby mid-K dwarf HIP 66074 was recently identified as host to a candidate super-Jupiter companion on a ∼300 day, almost edge-on, orbit, based on Gaia Data Release 3 (DR3) astrometry. Initial attempts at confirming the planetary nature of the signal based on publicly available radial-velocity (RV) observations uncovered an intriguing conundrum: the inferred RV semi-amplitude appears to be a factor of 15 smaller than the one predicted based on the Gaia solution (corresponding to a 7-MJup companion on a close to edge-on orbit). We present the results of intensive RV monitoring of HIP 66074 with the HARPS-N spectrograph. We detected the companion at the Gaia period, but with an extremely eccentric orbit (e = 0.948 ± 0.004), a semi-amplitude K = 93.9−7.0+9.4 m s−1, and a minimum mass mb sin ib = 0.79 ± 0.05 MJup. We used detailed simulations of Gaia astrometry with the DR3 time-span to show that the conundrum can be fully resolved by taking into account the combination of the initially sub-optimal RV sampling and systematic biases in the Gaia astrometric solution, which include an underestimation of the eccentricity and incorrect identification of orbital inclination, which has turned out to correspond to a close to face-on configuration (i ≲ 13°). With an estimated mass in the approximate range of 3 − 7 MJup, we find that HIP 66074b (≡Gaia-3b) is the first exoplanet candidate astrometrically detected by Gaia to be successfully confirmed based on RV follow-up observations.
Key words: astrometry / planetary systems / planets and satellites: individual: HIP 66074 b / planets and satellites: fundamental parameters / techniques: radial velocities / methods: data analysis
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.