Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095

• Main Authors: Murgas, F, Castro-González, A, Pallé, E, Pozuelos, F. J, Millholland, S, Foo, O, Korth, J, Marfil, E, Amado, P. J, Caballero, J. A, Christiansen, J. L, Ciardi, D. R, Collins, K. A, Di Sora, M, Fukui, A, Gan, T, Gonzales, E. J, Henning, Th, Herrero, E, Isopi, G, Jenkins, J. M, Lillo-Box, J, Lodieu, N, Luque, R, Mallia, F, Morales, J. C, Morello, G, Narita, N, Orell-Miquel, J, Parviainen, H, Pérez-Torres, M, Quirrenbach, A, Reiners, A, Ribas, I, Safonov, B. S, Seager, S, Schwarz, R. P, Schweitzer, A, Schlecker, M, Strakhov, I. A, Vanaverbeke, S, Watanabe, N, Winn, J. N, Zechmeister, M
• Format: Journal Article
• Language: English
• Published: 02-08-2023
• Subjects: Physics - Earth and Planetary Astrophysics; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.2304.09220

A&A 677, A182 (2023) The main scientific goal of TESS is to find planets smaller than Neptune
around stars that are bright enough to allow for further characterization
studies. Given our current instrumentation and detection biases, M dwarfs are
prime targets in the search for small planets that are in (or near) the
habitable zone of their host star. In this work, we use photometric
observations and CARMENES radial velocity measurements to validate a pair of
transiting planet candidates found by TESS. The data were fitted
simultaneously, using a Bayesian Markov chain Monte Carlo (MCMC) procedure and
taking into account the stellar variability present in the photometric and
spectroscopic time series. We confirm the planetary origin of the two
transiting candidates orbiting around TOI-2095 (LSPM J1902+7525). The star is a
nearby M dwarf ($d = 41.90 \pm 0.03$ pc, $T_{\rm eff} = 3759 \pm 87$ K, $V =
12.6$ mag), with a stellar mass and radius of $M_\star = 0.44 \pm 0.02 \;
M_\odot$ and $R_\star = 0.44 \pm 0.02 \; R_\odot$, respectively. The planetary
system is composed of two transiting planets: TOI-2095b, with an orbital period
of $P_b = 17.66484 \pm (7\times 10^{-5})$ days, and TOI-2095c, with $P_c =
28.17232 \pm (14\times 10^{-5})$ days. Both planets have similar sizes with
$R_b = 1.25 \pm 0.07 \; R_\oplus$ and $R_c = 1.33 \pm 0.08 \; R_\oplus$ for
planet b and planet c, respectively. Although we did not detect the induced RV
variations of any planet with significance, our CARMENES data allow us to set
stringent upper limits on the masses of these objects. We find $M_b < 4.1 \;
M_\oplus$ for the inner and $M_c < 7.4 \; M_\oplus$ for the outer planet (95%
confidence level). These two planets present equilibrium temperatures in the
range of 300-350 K and are close to the inner edge of the habitable zone of
their star.