K2-110 b: A massive mini-Neptune exoplanet
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-precisi...
Guardado en:
| Publicado: |
2017
|
|---|---|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046361_v604_n_p_Osborn http://hdl.handle.net/20.500.12110/paper_00046361_v604_n_p_Osborn |
| Aporte de: |
| Sumario: | 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 ± 0.1R ⊕ and a mass of 16.7 ± 3.2M ⊕ , 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 0.2M ⊕ hydrogen atmosphere over an 16.5M ⊕ 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 H 2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%. © 2017 ESO. |
|---|