TOI-4860 b, a short-period giant planet transiting an M3.5 dwarf

March 2024 • 2024A&A...683A.166A

Authors • Almenara, J. M. • Bonfils, X. • Bryant, E. M. • Jordán, A. • Hébrard, G. • Martioli, E. • Correia, A. C. M. • Astudillo-Defru, N. • Cadieux, C. • Arnold, L. • Artigau, É. • Bakos, G. Á. • Barros, S. C. C. • Bayliss, D. • Bouchy, F. • Boué, G. • Brahm, R. • Carmona, A. • Charbonneau, D. • Ciardi, D. R. • Cloutier, R. • Cointepas, M. • Cook, N. J. • Cowan, N. B. • Delfosse, X. • Dias do Nascimento, J. • Donati, J. -F. • Doyon, R. • Forveille, T. • Fouqué, P. • Gaidos, E. • Gilbert, E. A. • Gomes da Silva, J. • Hartman, J. D. • Hesse, K. • Hobson, M. J. • Jenkins, J. M. • Kiefer, F. • Kostov, V. B. • Laskar, J. • Lendl, M. • L'Heureux, A. • Martins, J. H. C. • Menou, K. • Moutou, C. • Murgas, F. • Polanski, A. S. • Rapetti, D. • Sedaghati, E. • Shang, H.

Abstract • We report the discovery and characterisation of a giant transiting planet orbiting a nearby M3.5V dwarf (d = 80.4pc, G = 15.1 mag, K=11.2mag, R_* = 0.358 ± 0.015 R_⊙, M_* = 0.340 ± 0.009 M_⊙). Using the photometric time series from TESS sectors 10, 36, 46, and 63 and near-infrared spectrophotometry from ExTrA, we measured a planetary radius of 0.77 ± 0.03 R_J and an orbital period of 1.52 days. With high-resolution spectroscopy taken by the CFHT/SPIRou and ESO/ESPRESSO spectrographs, we refined the host star parameters ([Fe/H] = 0.27 ± 0.12) and measured the mass of the planet (0.273 ± 0.006 M_J). Based on these measurements, TOI-4860 b joins the small set of massive planets (>80 M_E) found around mid to late M dwarfs (<0.4 R_⊙), providing both an interesting challenge to planet formation theory and a favourable target for further atmospheric studies with transmission spectroscopy. We identified an additional signal in the radial velocity data that we attribute to an eccentric planet candidate (e = 0.66 ± 0.09) with an orbital period of 427 ± 7 days and a minimum mass of 1.66 ± 0.26 M_J, but additional data would be needed to confirm this.

Links

• PREPRINT http://arxiv.org/abs/2308.01454
• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202346999/postscript
• ELECTR https://doi.org/10.1051%2F0004-6361%2F202346999
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2024A%26A...683A.166A
• PDF https://www.aanda.org/10.1051/0004-6361/202346999/pdf
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/683/A166
• DATA http://archive.eso.org/bin/ads2eso?2024A%26A...683A.166A