Two temperate Earth-mass planets orbiting the nearby star GJ1002
Journal
Date Issued
2023
Author(s)
Suárez Mascareño, A.
•
González-Álvarez, E.
•
Zapatero Osorio, M. R.
•
Lillo-Box, J.
•
Faria, J. P.
•
Passegger, V. M.
•
González Hernández, J. I.
•
Figueira, P.
•
•
Rebolo, R.
•
Pepe, F.
•
Santos, N. C.
•
•
Lovis, C.
•
Silva, A. M.
•
Ribas, I.
•
Amado, P. J.
•
Caballero, J. A.
•
Quirrenbach, A.
•
Reiners, A.
•
Zechmeister, M.
•
Adibekyan, V.
•
Alibert, Y.
•
Béjar, V. J. S.
•
•
•
•
Delisle, J. -B.
•
•
Dreizler, S.
•
Ehrenreich, D.
•
Hatzes, A. P.
•
Hara, N. C.
•
Henning, Th.
•
Kaminski, A.
•
López-González, M. J.
•
Martins, C. J. A. P.
•
•
Montes, D.
•
Pallé, E.
•
Pedraz, S.
•
Rodríguez, E.
•
Rodríguez-López, C.
•
Tal-Or, L.
•
Sousa, S.
•
Udry, S.
Abstract
We report the discovery and characterisation of two Earth-mass planets
orbiting in the habitable zone of the nearby M-dwarf GJ~1002 based on the
analysis of the radial-velocity (RV) time series from the ESPRESSO and CARMENES
spectrographs. The host star is the quiet M5.5~V star GJ~1002 (relatively faint
in the optical, $V \sim 13.8$ mag, but brighter in the infrared, $J \sim 8.3$
mag), located at 4.84 pc from the Sun.
We analyse 139 spectroscopic observations taken between 2017 and 2021. We
performed a joint analysis of the time series of the RV and full-width half
maximum (FWHM) of the cross-correlation function (CCF) to model the planetary
and stellar signals present in the data, applying Gaussian process regression
to deal with the stellar activity.
We detect the signal of two planets orbiting GJ~1002. GJ~1002~b is a planet
with a minimum mass $m_p \sin i $ of 1.08 $\pm$ 0.13 M$_{\oplus}$ with an
orbital period of 10.3465 $\pm$ 0.0027 days at a distance of 0.0457 $\pm$
0.0013 au from its parent star, receiving an estimated stellar flux of 0.67
$F_{\oplus}$. GJ~1002 c is a planet with a minimum mass $m_p \sin i $ of 1.36
$\pm$ 0.17 M$_{\oplus}$ with an orbital period of 21.202 $\pm$ 0.013 days at a
distance of 0.0738 $\pm$ 0.0021 au from its parent star, receiving an estimated
stellar flux of 0.257 $F_{\oplus}$. We also detect the rotation signature of
the star, with a period of 126 $\pm$ 15 days.
GJ~1002 is one of the few known nearby systems with planets that could
potentially host habitable environments. The closeness of the host star to the
Sun makes the angular sizes of the orbits of both planets ($\sim$ 9.7 mas and
$\sim$ 15.7 mas, respectively) large enough for their atmosphere to be studied
via high-contrast high-resolution spectroscopy with instruments such as the
future spectrograph ANDES for the ELT or the LIFE mission.
Volume
670
Start page
A5
Issn Identifier
0004-6361
Ads BibCode
2023A&A...670A...5S
Rights
open.access
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