Three planets transiting the evolved star EPIC 249893012: A hot 8.8-M super-Earth and two warm 14.7 and 10.2-M sub-Neptunes

We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star (M = 1.05 ± 0.05 M, R = 1.71 ± 0.04 R, T = 5430 ± 85 K). The star is just leaving the main sequence. We combined K2 photometry with...

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Detalles Bibliográficos
Autores: Hidalgo, D., Pallé, Enric, Alonso, Roi, Gandolfi, D., Fridlund, Malcolm, Nowak, G., Luque, Rafael, Hirano, T., Justesen, A. B., Cochran, W.D., Barragán, O., Spina, Lorenzo, Rodler, F., Albrecht, S., Anderson, David R., Amado, Pedro J., Bryant, E., Caballero, J. A., Cabrera, J., Csizmadia, S., Dai, F., León, Julia de, Deeg, H., Eigmuller, Ph., Endl, M., Erikson, A., Esposito, Massimiliano, Figueira, Pedro, Georgieva, I., Grziwa, S., Guenther, E. W., Hatzes, Artie P., Hjorth, M., Hoeijmakers, H. J., Kabath, P., Korth, J., Kuzuhara, M., Lafarga, M., Lampón, M., Leão, I. C., Livingston, J., Mathur, Savita, Montañés-Rodríguez, P., Morales, Juan Carlos, Murgas, Felipe, Nagel, Evangelos, Narita, N., Nielsen, L. D., Pätzold, M., Persson, C.M., Prieto-Arranz, J., Quirrenbach, Andreas, Rauer, Heike, Redfield, S., Reiners, Ansgar, Ribas, Ignasi, Smith, A. M. S., Šubjak, J., Van Eylen, V., Wilson, P. A.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/216808
Acceso en línea:http://hdl.handle.net/10261/216808
Access Level:acceso abierto
Palabra clave:Planetary systems
Planets and satellites: detection
Planets and satellites: fundamental parameters
Techniques: photometric
Techniques: radial velocities
Descripción
Sumario:We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star (M = 1.05 ± 0.05 M, R = 1.71 ± 0.04 R, T = 5430 ± 85 K). The star is just leaving the main sequence. We combined K2 photometry with IRCS adaptive-optics imaging and HARPS, HARPS-N, and CARMENES high-precision radial velocity measurements to confirm the planetary system, determine the stellar parameters, and measure radii, masses, and densities of the three planets. With an orbital period of 3.5949 days, a mass of 8.75 M, and a radius of 1.95 R, the inner planet b is compatible with nickel-iron core and a silicate mantle (ρ = 6.39 g cm). Planets c and d with orbital periods of 15.624 and 35.747 days, respectively, have masses and radii of 14.67 M and 3.67 R and 10.18 M and 3.94 R, respectively, yielding a mean density of 1.62 and 0.91 g cm, respectively. The radius of planet b lies in the transition region between rocky and gaseous planets, but its density is consistent with a rocky composition. Its semimajor axis and the corresponding photoevaporation levels to which the planet has been exposed might explain its measured density today. In contrast, the densities and semimajor axes of planets c and d suggest a very thick atmosphere. The singularity of this system, which orbits a slightly evolved star that is just leaving the main sequence, makes it a good candidate for a deeper study from a dynamical point of view.

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