A sub-Neptune planet around TOI-1695 discovered and characterized with SPIRou and TESS

Bibliographic Details
Title: A sub-Neptune planet around TOI-1695 discovered and characterized with SPIRou and TESS
Authors: Kiefer, F., Hébrard, G., Martioli, E., Artigau, E., Doyon, R., Donati, J. -F., Cadieux, C., Carmona, A., Ciardi, D. R., Cristofari, P. I., de Almeida, L., Figueira, P., Gaidos, E., Gonzales, E., Lecavelier, A., Stassun, K. G., Arnold, L., Benneke, B., Boisse, I., Bonfils, X., Cook, N. J., Cortés-Zuleta, P., Delfosse, X., Nascimento, J. Dias do, Fausnaugh, M., Fong, W., Fouqué, P., Forveille, T., da Silva, J. Gomes, Hesse, K., Kóspál, Á., Lewis, H., Liu, C. -F., Martins, J. H. C., Paegert, M., Seager, S., Shang, H., Twicken, J. D., Vandal, T., Vinatier, S., Widemann, T., Winn, J. N.
Source: A&A 670, A136 (2023)
Publication Year: 2022
Collection: Astrophysics
Subject Terms: Astrophysics - Earth and Planetary Astrophysics
More Details: TOI-1695 is a V-mag=13 M-dwarf star from the northern hemisphere at 45$\,$pc from the Sun, around which a 3.134-day periodic transit signal from a super-Earth candidate was identified in TESS photometry. With a transit depth of 1.3$\,$mmag, the radius of candidate TOI-1695.01 was estimated by the TESS pipeline to be 1.82$\,$R$_\oplus$ with an equilibrium temperature of $\sim 620\,$K. We successfully detect a reflex motion of the star and establish it is due to a planetary companion at an orbital period consistent with the photometric transit period thanks to a year-long radial-velocity monitoring of TOI-1695 by the SPIRou infrared spectropolarimeter. We use and compare different methods to reduce and analyse those data. We report a 5.5-$\sigma$ detection of the planetary signal, giving a mass of $5.5 \pm 1.0\,$M$_\oplus$ and a radius of $2.03 \pm 0.18\,$R$_\oplus$. We derive a mean equilibrium planet temperature of $590 \pm 90\,$K. The mean density of this small planet of $3.6 \pm 1.1\,$g$\,$cm$^{-3}$ is similar (1.7-$\sigma$ lower) than that of the Earth. It leads to a non-negligible fraction of volatiles in its atmosphere with $f_{H,He}=0.28^{+0.46}_{-0.23}$% or $f_\text{water}=23 \pm 12$%. TOI-1695$\,$b is a new sub-Neptune planet at the border of the M-dwarf radius valley that can help test formation scenarios for super-Earth/sub-Neptune-like planets.
Comment: 15 pages (+9 appendix pages), 19 figures, 8 tables, accepted for publication in A&A
Document Type: Working Paper
DOI: 10.1051/0004-6361/202245129
Access URL: http://arxiv.org/abs/2211.06205
Accession Number: edsarx.2211.06205
Database: arXiv
More Details
DOI:10.1051/0004-6361/202245129