Exoplanetology: Exoplanets & Exomoons

Characterizing Planetary Systems With SPIRou: Detection Of A Sub-Neptune In A 6 day Period Orbit Around The M Dwarf Gl 410

By Keith Cowing

Status Report

astro-ph.EP

April 7, 2025

Filed under astro-ph.EP, astronomy, CFHT/SPIRou, exoplanet, Gl 410, imaging, M dwarf, SOPHIE, sub-Neptune

Characterizing Planetary Systems With SPIRou: Detection Of A Sub-Neptune In A 6 day Period Orbit Around The M Dwarf Gl 410 — Results of the RadVel MCMC Keplerian circular orbital model with one planet of the SPIRou RV time-series. Each column represents the results for each set of data reductions: LBL at |Vtot| > 10 km s−1 , wPCA and Wapiti. The panel a shows the RV time-series, the panel b displays the residuals as a function of time, the panel c plots the phase-folded RVs together with the best fit model (blue line) and the panel d displays the corner plots of Mb sin(i) and semi-mayor axis of the planet detected. The red circles in panel c are the RVs binned in 0.08 units of the orbital phase. In all RVs, the RadVel RV jitter σSPIRou described in Table 6 is added in quadrature to the RV uncertainties. The orbital, planet, and fit parameters of the models are summarized in Table 6. Corner plots of the circular fit are provided in the Appendix (Figs. E.3, E.4 and E.5). Our baseline solution is the model based on the SPIRou wPCA data-set. astro-ph.EP

The search of exoplanets around nearby M dwarfs is a crucial milestone to perform the census of planetary systems in the vicinity of our Solar System. Since 2018 our team is carrying a radial-velocity blind search program for planets around nearby M dwarfs with the near-IR spectro-polarimeter and velocimeter SPIRou at the CFHT and the optical velocimeter SOPHIE at the OHP in France.

Here we present our results on Gl 410, a 0.55 M_sun 480+-150 Myr old active M dwarf distant 12 pc. We use the line-by-line (LBL) technique to measure the RVs with SPIRou and the template matching method with SOPHIE. Three different methods, two based in principal component analysis (PCA), are used to clean the SPIRou RVs for systematics. Gaussian processes (GP) modeling is applied to correct the SOPHIE RVs for stellar activity. The l1 and apodize sine periodogram (ASP) analysis is used to search for planetary signals in the SPIRou data taking into account activity indicators.

We analyse TESS data and search for planetary transits. We report the detection of a M sin(i)=8.4+-1.3 M_earth sub-Neptune planet at a period of 6.020+-0.004 days in circular orbit with SPIRou. The same signal, although with lower significance, is also retrieved in the SOPHIE RV data after correction for activity using a GP trained on SPIRou’s longitudinal magnetic field (Bl) measurements. TESS data indicates that the planet is not transiting. We find within the SPIRou wPCA RVs tentative evidence for two additional planetary signals at 2.99 and 18.7 days.

In conclusion, infrared RVs are a powerful method to detect extrasolar planets around active M dwarfs, care should be taken however to correct/filter systematics generated by residuals of the telluric correction or small structures in the detector plane. The LBL technique combined with PCA offers a promising way to reach this objective. Further monitoring of Gl 410 is necessary.

A. Carmona (1), X. Delfosse (1), M. Ould-Elhkim (2), P. Cortés-Zuleta (3), N. C. Hara (4), E. Artigau (5 and 6), C. Moutou (2), A. C. Petit (7), L. Mignon (1), J.F. Donati (2), N.J. Cook (5), J. Gagné (8 and 5), T. Forveille (1), R.F. Diaz (9), E. Martioli (10 and 11), L. Arnold (12), C. Cadieux (5), I. Boisse (4), J. Morin (13), P. Petit (2), P. Fouqué (2), X. Bonfils (1), G. Hébrard (11), L. Acuña (4 and 14), J.-D. do Nascimento Jr (15 and 16), R. Cloutier (17), N. Astudillo-Defru (18), F. Bouchy (19), V. Bourrier (19), S. Dalal (11), M. Deleuil (4), R. Doyon (5), X. Dumusque (19), S. Grouffal (4), N. Heidari (10), S. Hoyer (4), P. Larue (1), F. Kiefer (11), A. Santerne (4), D. Ségransan (19), J. Serrano Bell (9 and 11), M. Stalport (20), S. Sulis (4), S. Udry (19), H. Vivien (4) ((1) Univ. Grenoble Alpes, France, (2) Université de Toulouse, France, (3) University of St Andrews, UK, (4) Aix Marseille Université, France, (5) Institute for Research on Exoplanets, Université de Montréal, Canada, (6) Observatoire du Mont-Mégantic, Université de Montréal, Canada, (7) Université Côte d’Azur, Observatoire de la Côte d’Azur, Nice, France, (8) Planétarium de Montréal, Canada, (9) International Center for Advanced Studies, Buenos Aires, Argentina, (10) Laboratório Nacional de Astrofísica, Itajuba, Brazil, (11) Institut d’Astrophysique de Paris, Paris, France, (12) Canada France Hawaii Telescope Corporation, Kamuela, USA, (13) Université de Montpellier, France, (14) Max-Planck-Institut for Astronomie, Heidelberg, Germany, (15) Center for Astrophysics, Harvard & Smithsonian, USA, (16) Univ. Federal do Rio Grande do Norte, Natal, Brazil, (17) McMaster University, Hamilton, Canada, (18) Universidad Católica de la Santísima Concepción, Concepción, Chile, (19) Observatoire Astronomique de l’Université de Genève, Switzerland, (20) Université de Liège, Liège, Belgium)

Comments: Accepted by A&A, 4 April 2025; 35 pages
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2504.03572 [astro-ph.EP] (or arXiv:2504.03572v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2504.03572
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Submission history
From: Andres Carmona
[v1] Fri, 4 Apr 2025 16:23:52 UTC (15,388 KB)
https://arxiv.org/abs/2504.03572
Astrobiology

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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