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arXiv · 2106.04536

TOI-1278 B: SPIRou unveils a rare Brown Dwarf Companion in Close-In Orbit around an M dwarf

Étienne Artigau·Guillaume Hébrard·Charles Cadieux·Thomas Vandal·Neil J. Cook·René Doyon·Jonathan Gagné·Claire Moutou·Eder Martioli·Antonio Frasca·Farbod Jahandar·David Lafrenière·Lison Malo·Jean-François Donati·Pia Cortes-Zuleta·Isabelle Boisse·Xavier Delfosse·Andres Carmona·Pascal Fouqué·Julien Morin·Jason Rowe·Giuseppe Marino·Riccardo Papini·David R. Ciardi·Michael B. Lund·Jorge H. C. Martins·Stefan Pelletier·Luc Arnold·François Bouchy·Thierry Forveille·Nuno C. Santos·Xavier Bonfils·Pedro Figueira·Michael Fausnaugh·George Ricker·David W. Latham·Sara Seager·Joshua N. Winn·Jon M. Jenkins·Eric B. Ting·Guillermo Torres·João Gomes da Silva
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Abstract

We present the discovery of an $18.5\pm0.5$M$_{\rm Jup}$ brown dwarf (BD) companion to the M0V star TOI-1278. The system was first identified through a percent-deep transit in TESS photometry; further analysis showed it to be a grazing transit of a Jupiter-sized object. Radial velocity (RV) follow-up with the SPIRou near-infrared high-resolution velocimeter and spectropolarimeter in the framework of the 300-night SPIRou Legacy Survey (SLS) carried out at the Canada-France-Hawaii Telescope (CFHT) led to the detection of a Keplerian RV signal with a semi-amplitude of $2306\pm10$ m/s in phase with the 14.5-day transit period, having a slight but non-zero eccentricity. The intermediate-mass ratio ($M_\star/M_{\rm{comp}} \sim31$) is unique for having such a short separation ($0.095\pm0.001$ AU) among known M-dwarf systems. Interestingly, M dwarf-brown dwarf systems with similar mass ratios exist with separations of tens to thousands of AUs.

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Étienne Artigau, Guillaume Hébrard, Charles Cadieux, Thomas Vandal, Neil J. Cook, René Doyon, Jonathan Gagné, Claire Moutou, Eder Martioli, Antonio Frasca, Farbod Jahandar, David Lafrenière, Lison Malo, Jean-François Donati, Pia Cortes-Zuleta, Isabelle Boisse, Xavier Delfosse, Andres Carmona, Pascal Fouqué, Julien Morin, Jason Rowe, Giuseppe Marino, Riccardo Papini, David R. Ciardi, Michael B. Lund, Jorge H. C. Martins, Stefan Pelletier, Luc Arnold, François Bouchy, Thierry Forveille, Nuno C. Santos, Xavier Bonfils, Pedro Figueira, Michael Fausnaugh, George Ricker, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Eric B. Ting, Guillermo Torres, João Gomes da Silva. 2021-06-08. TOI-1278 B: SPIRou unveils a rare Brown Dwarf Companion in Close-In Orbit around an M dwarf. https://doi.org/10.3847/1538-3881%2Fac096d

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