A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2022

A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone

M. Damasso
  • Function : Author
M. Perger
  • Function : Author
M. Pérez-Torres
  • Function : Author
A. Sozzetti
  • Function : Author
N. C. Hara
  • Function : Author
A. Quirrenbach
  • Function : Author
M. R. Zapatero Osorio
  • Function : Author
N. Astudillo-Defru
  • Function : Author
J. I. González Hernández
  • Function : Author
A. Suárez Mascareno
  • Function : Author
P. J. Amado
  • Function : Author
J. Lillo-Box
  • Function : Author
Y. Alibert
  • Function : Author
J. A. Caballero
  • Function : Author
C. Cifuentes
  • Function : Author
P. Figueira
  • Function : Author
D. Galadí-Enríquez
  • Function : Author
A. P. Hatzes
  • Function : Author
Th. Henning
  • Function : Author
A. Kaminski
  • Function : Author
M. Mayor
  • Function : Author
F. Murgas
  • Function : Author
D. Montes
  • Function : Author
M. Pinamonti
  • Function : Author
A. Reiners
  • Function : Author
I. Ribas
  • Function : Author
V. J. S. Béjar
  • Function : Author
A. Schweitzer
  • Function : Author
M. Zechmeister
  • Function : Author

Abstract

Context. Statistical analyses based on Kepler data show that most of the early-type M dwarfs host multi-planet systems consisting of Earth- to sub-Neptune-sized planets with orbital periods of up to ~250 days, and that at least one such planet is likely located within the habitable zone. M dwarfs are therefore primary targets to search for potentially habitable planets in the solar neighbourhood.
Aims: We investigated the presence of planetary companions around the nearby (7.6 pc) and bright (V = 9 mag) early-type M dwarf Gl 514, analysing 540 radial velocities collected over nearly 25 yr with the HIRES, HARPS, and CARMENES spectrographs.
Methods: The data are affected by time-correlated signals at the level of 2-3 m s−1 due to stellar activity, which we filtered out, testing three different models based on Gaussian process regression. As a sanity cross-check, we repeated the analyses using HARPS radial velocities extracted with three different algorithms. We used HIRES radial velocities and Hipparcos-Gaia astrometry to put constraints on the presence of long-period companions, and we analysed TESS photometric data.
Results: We find strong evidence that Gl 514 hosts a super-Earth on a likely eccentric orbit, residing in the conservative habitable zone for nearly 34% of its orbital period. The planet Gl 514b has minimum mass mb sin ib = 5.2 ± 0.9 M, orbital period Pb = 140.43 ± 0.41 days, and eccentricity eb = 0.45−0.14+0.15. No evidence for transits is found in the TESS light curve. There is no evidence for a longer period companion in the radial velocities and, based on astrometry, we can rule out a ~0.2 MJup planet at a distance of ~3-10 astronomical units, and massive giant planets and brown dwarfs out to several tens of astronomical units. We discuss the possible presence of a second low-mass companion at a shorter distance from the host than Gl 514 b.
Conclusions: Gl 514 b represents an interesting science case for studying the habitability of planets on eccentric orbits. We advocate for additional spectroscopic follow-up to get more accurate and precise planetary parameters. Further follow-up is also needed to investigate the presence of additional planetary signals of less than 1 m s−1.

Tables A.1-A.4 are only available at the CDS via anonymous ftp to ftp://cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/666/A187

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insu-03860283 , version 1 (19-11-2022)

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M. Damasso, M. Perger, J. M. Almenara, D. Nardiello, M. Pérez-Torres, et al.. A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone. Astronomy and Astrophysics - A&A, 2022, 666, ⟨10.1051/0004-6361/202243522⟩. ⟨insu-03860283⟩
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