Issue |
A&A
Volume 651, July 2021
|
|
---|---|---|
Article Number | A93 | |
Number of page(s) | 20 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202141141 | |
Published online | 21 July 2021 |
HADES RV programme with HARPS-N at TNG
XIV. A candidate super-Earth orbiting the M-dwarf GJ 9689 with a period close to half the stellar rotation period★,★★
1
INAF – Osservatorio Astronomico di Palermo,
Piazza del Parlamento 1,
90134
Palermo,
Italy
e-mail: jesus.maldonado@inaf.it
2
INAF – Osservatorio Astrofisico di Torino,
Via Osservatorio 20,
10025
Pino Torinese,
Italy
3
INAF – Osservatorio Astrofisico di Catania,
Via S. Sofia 78,
95123
Catania,
Italy
4
Centro de Astrobiología (CSIC-INTA),
Carretera de Ajalvir km 4,
28850
Torrejón de Ardoz,
Madrid,
Spain
5
Fundación Galileo Galilei-INAF,
Rambla José Ana Fernández Pérez 7,
38712
Breña Baja,
TF,
Spain
6
INAF – Osservatorio Astronomico di Brera,
Via E. Bianchi 46,
23807
Merate,
Italy
7
Institut de Ciéncies de l’Espai (ICE, CSIC),
Campus UAB, Carrer de Can Magrans s/n,
08193
Bellaterra,
Spain
8
Institut d’Estudis Espacials de Catalunya (IEEC),
08034
Barcelona,
Spain
9
Instituto de Astrofísica de Canarias,
38205
La Laguna,
Tenerife,
Spain
10
Universidad de La Laguna, Departamento Astrofísica,
38206
La Laguna,
Tenerife,
Spain
11
INAF – Osservatorio Astronomico di Trieste,
Via Tiepolo 11,
34143
Trieste,
Italy
12
INAF – Osservatorio Astronomico di Cagliari and REM,
Via della Scienza, 5,
09047
Selargius
CA,
Italy
13
INAF – Osservatorio Astronomico di Capodimonte,
Salita Moiariello 16,
80131
Napoli,
Italy
14
INAF – Osservatorio Astronomico di Padova,
vicolo dell’Osservatorio 5,
35122
Padova,
Italy
15
Dipartimento di Fisica e Astronomia Galileo Galilei,
Vicolo Osservatorio 3,
35122
Padova,
Italy
Received:
20
April
2021
Accepted:
12
May
2021
Context. It is now well-established that small, rocky planets are common around low-mass stars. However, the detection of such planets is challenged by the short-term activity of host stars.
Aims. The HARPS-N red Dwarf Exoplanet Survey programme is a long-term project at the Telescopio Nazionale Galileo aimed at monitoring nearby, early-type, M dwarfs, using the HARPS-N spectrograph to search for small, rocky planets.
Methods. A total of 174 HARPS-N spectroscopic observations of the M0.5V-type star GJ 9689 taken over the past seven years have been analysed. We combined these data with photometric measurements to disentangle signals related to the stellar activity of the star from possible Keplerian signals in the radial velocity data. We ran an MCMC analysis, applying Gaussian process regression techniques to model the signals present in the data.
Results. We identify two periodic signals in the radial velocity time series, with periods of 18.27 and 39.31 d. The analysis of the activity indexes, photometric data, and wavelength dependency of the signals reveals that the 39.31 d signal corresponds to the stellar rotation period. On the other hand, the 18.27 d signal shows no relation to any activity proxy or the first harmonic of the rotation period. We, therefore, identify it as a genuine Keplerian signal. The best-fit model describing the newly found planet, GJ 9689 b, corresponds to an orbital period of Pb = 18.27 ± 0.01 d and a minimum mass of MP sini = 9.65 ± 1.41 M⊕.
Key words: techniques: spectroscopic / techniques: radial velocities / stars: late-type / planetary systems / stars: individual: GJ 9689
Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/651/A93
© ESO 2021
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