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Journal Articles Astronomy and Astrophysics - A&A Year : 2022

A detailed analysis of the Gl 486 planetary system

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J. A. Caballero
  • Function : Author
E. González-Álvarez
  • Function : Author
M. Brady
  • Function : Author
T. Trifonov
  • Function : Author
T. G. Ellis
  • Function : Author
C. Dorn
  • Function : Author
C. Cifuentes
  • Function : Author
K. Molaverdikhani
  • Function : Author
J. L. Bean
  • Function : Author
T. Boyajian
  • Function : Author
E. Rodríguez
  • Function : Author
J. Sanz-Forcada
  • Function : Author
M. R. Zapatero Osorio
  • Function : Author
C. Abia
  • Function : Author
P. J. Amado
  • Function : Author
N. Anugu
  • Function : Author
V. J. S. Béjar
  • Function : Author
C. L. Davies
  • Function : Author
S. Dreizler
  • Function : Author
F. Dubois
  • Function : Author
J. Ennis
  • Function : Author
N. Espinoza
  • Function : Author
C. D. Farrington
  • Function : Author
A. García López
  • Function : Author
T. Gardner
  • Function : Author
A. P. Hatzes
  • Function : Author
Th. Henning
  • Function : Author
E. Herrero
  • Function : Author
E. Herrero-Cisneros
  • Function : Author
A. Kaminski
  • Function : Author
D. Kasper
  • Function : Author
R. Klement
  • Function : Author
S. Kraus
  • Function : Author
A. Labdon
  • Function : Author
C. Lanthermann
  • Function : Author
M. J. López González
  • Function : Author
R. Luque
  • Function : Author
A. W. Mann
  • Function : Author
E. Marfil
  • Function : Author
J. D. Monnier
  • Function : Author
D. Montes
  • Function : Author
J. C. Morales
  • Function : Author
E. Pallé
  • Function : Author
S. Pedraz
  • Function : Author
A. Quirrenbach
  • Function : Author
S. Reffert
  • Function : Author
A. Reiners
  • Function : Author
I. Ribas
  • Function : Author
C. Rodríguez-López
  • Function : Author
G. Schaefer
  • Function : Author
A. Schweitzer
  • Function : Author
A. Seifahrt
  • Function : Author
B. R. Setterholm
  • Function : Author
Y. Shan
  • Function : Author
D. Shulyak
  • Function : Author
E. Solano
  • Function : Author
K. R. Sreenivas
  • Function : Author
G. Stefánsson
  • Function : Author
J. Stürmer
  • Function : Author
H. M. Tabernero
  • Function : Author
L. Tal-Or
  • Function : Author
T. ten Brummelaar
  • Function : Author
S. Vanaverbeke
  • Function : Author
K. von Braun
  • Function : Author
A. Youngblood
  • Function : Author
M. Zechmeister
  • Function : Author

Abstract

Context. The Gl 486 system consists of a very nearby, relatively bright, weakly active M3.5 V star at just 8 pc with a warm transiting rocky planet of about 1.3 R and 3.0 M. It is ideal for both transmission and emission spectroscopy and for testing interior models of telluric planets.
Aims: To prepare for future studies, we aim to thoroughly characterise the planetary system with new accurate and precise data collected with state-of-the-art photometers from space and spectrometers and interferometers from the ground.
Methods: We collected light curves of seven new transits observed with the CHEOPS space mission and new radial velocities obtained with MAROON-X at the 8.1 m Gemini North telescope and CARMENES at the 3.5 m Calar Alto telescope, together with previously published spectroscopic and photometric data from the two spectrographs and TESS. We also performed near-infrared interferometric observations with the CHARA Array and new photometric monitoring with a suite of smaller telescopes (AstroLAB, LCOGT, OSN, TJO). This extraordinary and rich data set was the input for our comprehensive analysis.
Results: From interferometry, we measure a limb-darkened disc angular size of the star Gl 486 at θLDD = 0.390 ± 0.018 mas. Together with a corrected Gaia EDR3 parallax, we obtain a stellar radius R* = 0.339 ± 0.015 R. We also measure a stellar rotation period at Prot = 49.9 ± 5.5 days, an upper limit to its XUV (5-920 A) flux informed by new Hubble/STIS data, and, for the first time, a variety of element abundances (Fe, Mg, Si, V, Sr, Zr, Rb) and C/O ratio. Moreover, we imposed restrictive constraints on the presence of additional components, either stellar or sub-stellar, in the system. With the input stellar parameters and the radial-velocity and transit data, we determine the radius and mass of the planet Gl 486 b at Rp = 1.343−0.062+0.063 R and Mp = 3.00−0.12+0.13 M, with relative uncertainties of the planet radius and mass of 4.7% and 4.2%, respectively. From the planet parameters and the stellar element abundances, we infer the most probable models of planet internal structure and composition, which are consistent with a relatively small metallic core with respect to the Earth, a deep silicate mantle, and a thin volatile upper layer. With all these ingredients, we outline prospects for Gl 486 b atmospheric studies, especially with forthcoming James Webb Space Telescope (Webb) observations.
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Dates and versions

insu-03860302 , version 1 (19-11-2022)

Licence

Attribution - CC BY 4.0

Identifiers

Cite

J. A. Caballero, E. González-Álvarez, M. Brady, T. Trifonov, T. G. Ellis, et al.. A detailed analysis of the Gl 486 planetary system. Astronomy and Astrophysics - A&A, 2022, 665, ⟨10.1051/0004-6361/202243548⟩. ⟨insu-03860302⟩
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