IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
K2-110 b: A massive mini-Neptune exoplanet
Autor/es:
BARROS, S.C.C.; MALAVOLTA, L.; DEMANGEON, O.; BARRADO, D.; BOUCHY, F.; CHARBONNEAU, D.; DIÁZ, R.F.; KING, G.W.; LILLO-BOX, J.; MARMIER, M.; PEPE, F.; UDRY, S.; SANTERNE, A.; DUMUSQUE, X.; HOJJATPANAH, S.; ALMENARA, J.-M.; BOISSE, I.; CAMERON, A.C.; DELGADO MENA, E.; KIRK, J.; LATHAM, D.; LOVIS, C.; MOLINARI, E.; SOUSA, S.G.; OSBORN, H.P.; SANTOS, N.C.; ARMSTRONG, D.J.; ADIBEKYAN, V.; BAYLISS, D.; BROWN, D.J.A.; DELEUIL, M.; HÉBRARD, G.; LAM, K.W.F.; LOUDEN, T.M.; MCCORMAC, J.; POLLACCO, D.; WALKER, S.R.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Año: 2017 vol. 604
ISSN:
0004-6361
Resumen:
We report the discovery of the exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With a V-band magnitude of 11.9, K2-110 is particularly amenable to RV follow-up. A joint analysis of K2 photometry and high-precision RVs from 28 HARPS and HARPS-N spectra reveal it to have a radius of 2.6 ± 0.1Râ?? and a mass of 16.7 ± 3.2Mâ??, hence a density of 5.2 ± 1.2 g cm-3, making it one of the most massive planets yet to be found with a sub-Neptune radius. When accounting for compression, the resulting Earth-like density is best fitted by a 0.2Mâ?? hydrogen atmosphere over an 16.5Mâ?? Earth-like interior, although the planet could also have significant water content. At 0.1 AU, even taking into account the old stellar age of 8 ± 3 Gyr, the planet is unlikely to have been significantly affected by EUV evaporation. However the planet likelydisc-migrated to its current position making the lack of a thick H2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%.