A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS

ASTUDILLO-DEFRU, N.; CLOUTIER, R.; WANG, S.X.; TESKE, J.; BRAHM, R.; HELLIER, C.; RICKER, G.; VANDERSPEK, R.; LATHAM, D.; SEAGER, S.; WINN, J.N.; JENKINS, J.M.; COLLINS, K.A.; STASSUN, K.G.; ZIEGLER, C.; ALMENARA, J.M.; ANDERSON, D.R.; ARTIGAU, E.; BONFILS, X.; BOUCHY, F.; BRICEÑO, C.; BUTLER, R.P.; CHARBONNEAU, D.; CONTI, D.M.; CRANE, J.; CROSSFIELD, I.J.M.; DAVIES, M.; DELFOSSE, X.; DÍAZ, R.F.; DOYON, R.; DRAGOMIR, D.; EASTMAN, J.D.; ESPINOZA, N.; ESSACK, Z.; FENG, F.; FIGUEIRA, P.; FORVEILLE, T.; GAN, T.; GLIDDEN, A.; GUERRERO, N.; HART, R.; HENNING, TH.; HORCH, E.P.; ISOPI, G.; JENKINS, J.S.; JORDÁN, A.; KIELKOPF, J.F.; LAW, N.; LOVIS, C.; MALLIA, F.; MANN, A.W.; DE MEDEIROS, J.R.; MELO, C.; MENNICKENT, R.E.; MIGNON, L.; MURGAS, F.; NUSDEO, D.A.; PEPE, F.; RELLES, H.M.; ROSE, M.; SANTOS, N.C.; SÉGRANSAN, D.; SHECTMAN, S.; SHPORER, A.; SMITH, J.C.; TORRES, P.; UDRY, S.; VILLASENOR, J.; WINTERS, J.G.; ZHOU, G.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2020 vol. 636

0004-6361

We report the detection of a transiting super-Earth-sized planet (R = 1.39 ± 0.09 R⊕ ) in a 1.4-day orbit around L 168-9 (TOI-134), a bright M1V dwarf (V = 11, K = 7.1) located at 25.15 ± 0.02 pc. The host star was observed in the first sector of the Transiting Exoplanet Survey Satellite (TESS) mission. For confirmation and planet mass measurement purposes, this was followed up with ground-based photometry, seeing-limited and high-resolution imaging, and precise radial velocity (PRV) observations using the HARPS and Magellan/PFS spectrographs. By combining the TESS data and PRV observations, we find the mass of L 168-9 b to be 4.60 ± 0.56 M⊕ and thus the bulk density to be 1.74-0.33+0.44 times higher than that of the Earth. The orbital eccentricity is smaller than 0.21 (95% confidence). This planet is a level one candidate for the TESS mission´s scientific objective of measuring the masses of 50 small planets, and it is one of the most observationally accessible terrestrial planets for future atmospheric characterization.