| Issue |
A&A
Volume 675, July 2023
|
|
|---|---|---|
| Article Number | A187 | |
| Number of page(s) | 18 | |
| Section | Planets and planetary systems | |
| DOI | https://doi.org/10.1051/0004-6361/202346472 | |
| Published online | 21 July 2023 | |
Wapiti: A data-driven approach to correct for systematics in RV data
Application to SPIRou data of the planet-hosting M dwarf GJ 251★
1
Université de Toulouse, UPS-OMP, IRAP,
14 avenue E. Belin,
31400
Toulouse, France
e-mail: merwan.ould-elhkim@irap.omp.eu
2
Trottier Institute for Research on Exoplanets, Université de Montréal, Département de Physique,
C.P. 6128,
Succ. Centre-ville,
Montréal QC
H3C 3J7, Canada
3
Observatoire du Mont-Mégantic, Université de Montréal, Département de Physique,
C.P. 6128,
Succ. Centre-ville,
Montréal QC
H3C 3J7, Canada
4
Univ. Grenoble Alpes, CNRS, IPAG,
38000
Grenoble, France
5
Center for Astrophysics, Harvard & Smithsonian,
60 Garden Street,
Cambridge, MA
02138, USA
6
Institut d’Astrophysique de Paris, CNRS, UMR 7095, Sorbonne Université,
98 bis bd Arago,
75014
Paris, France
7
Laboratório Nacional de Astrofísica,
Rua Estados Unidos 154,
37504-364,
Itajubá MG, Brazil
8
Département d’astronomie, Université de Genève,
Chemin des Maillettes 51,
1290
Versoix, Switzerland
9
Department of Physics, University of Oxford,
Oxford
OX1 3RH, UK
10
Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP,
Rua das Estrelas,
4150-762
Porto, Portugal
Received:
21
March
2023
Accepted:
30
April
2023
Context. Recent advances in the development of precise radial velocity (RV) instruments in the near-infrared (near-IR) domain, such as SPIRou, have facilitated the study of M-type stars to more effectively characterize planetary systems. However, the near-IR presents unique challenges in exoplanet detection due to various sources of planet-independent signals which can result in systematic errors in the RV data.
Aims. In order to address the challenges posed by the detection of exoplanetary systems around M-type stars using near-IR observations, we introduced a new data-driven approach for correcting systematic errors in RV data. The effectiveness of this method is demonstrated through its application to the star GJ 251.
Methods. Our proposed method, Weighted principAl comPonent reconsTructIon (referred to as Wapiti), used a dataset of per-line RV time series generated by the line-by-line (LBL) algorithm and employed a weighted Principal Component Analysis (wPCA) to reconstruct the original RV time series. A multistep process was employed to determine the appropriate number of components, with the ultimate goal of subtracting the wPCA reconstruction of the per-line RV time series from the original data in order to correct systematic errors.
Results. The application of Wapiti to GJ 251 successfully eliminated spurious signals from the RV time series and enabled the first detection in the near-IR of GJ 251b, a known temperate super-Earth with an orbital period of 14.2 days. This demonstrates that, even when systematics in SPIRou data are unidentified, it is still possible to effectively address them and fully realize the instrument’s capability for exoplanet detection. Additionally, in contrast to the use of optical RVs, this detection did not require us to filter stellar activity, highlighting a key advantage of near-IR RV measurements.
Key words: techniques: radial velocities / techniques: spectroscopic / methods: data analysis / stars: individual: GJ 251 / planetary systems / stars: low-mass
Based on observations obtained at the Canada–France–Hawaii Telescope (CFHT) which is operated from the summit of Maunakea by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. The observations at the Canada–France–Hawaii Telescope were performed with care and respect from the summit of Maunakea which is a significant cultural and historic site. Based on observations obtained with SPIRou, an international project led by Institut de Recherche en Astrophysique et Planétologie, Toulouse, France. SPIRou is an acronym for SPectropolarimetre InfraROUge (infrared spectropolarimeter).
© 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.