http://arxiv.org/abs/2211.06205
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.
F. Kiefer, G. Hébrard, E. Martioli, et. al.
Mon, 14 Nov 22
59/69
Comments: 15 pages (+9 appendix pages), 19 figures, 8 tables