We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-sized planet in an 8.9-d orbit transiting a V=12.6mag, metal-poor ([Fe/H] = -0.65 ± 0.10) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-d orbit around a V=12.6mag G6V ([Fe/H] = +0.10 ± 0.10) star in K2 campaign 10. Our results are based on K2 time-series photometry combined with high-spatial resolution imaging and high-precision radial velocity measurements. We present the first mass measurement of K2-180b. K2-180b has a mass of Mp = 11.3 ± 1.9M⊕ and a radius of Rp = 2.2 ± 0.1R⊕, yielding a mean density of ρp = 5.6 ± 1.9 g cm-3, suggesting a rocky composition. Given its radius, K2-180b is above the region of the so-called 'planetary radius gap'. K2-180b is in addition not only one of the densest mini-Neptune-sized planets, but also one of the few mini-Neptune-sized planets known to transit a metal-poor star. We also constrain the planetary and orbital parameters of K2-140b and show that, given the currently available Doppler measurements, the eccentricity is consistent with zero, contrary to the results of a previous study.
K2-140b and K2-180b - Characterization of a hot Jupiter and a mini-Neptune from the K2 mission / Korth, J.; Csizmadia, S.; Gandolfi, D.; Fridlund, M.; Patzold, M.; Hirano, T.; Livingston, J.; Persson, C. M.; Deeg, H. J.; Justesen, A. B.; Barragan, O.; Grziwa, S.; Endl, M.; Tronsgaard, R.; Dai, F.; Cochran, W. D.; Albrecht, S.; Alonso, R.; Cabrera, J.; Cauley, P. W.; Cusano, F.; Eigmuller, P.; Erikson, A.; Esposito, M.; Guenther, E. W.; Hatzes, A. P.; Hidalgo, D.; Kuzuhara, M.; Montanes, P.; Napolitano, N. R.; Narita, N.; Niraula, P.; Nespral, D.; Nowak, G.; Palle, E.; Petrillo, C. E.; Redfield, S.; Prieto-Arranz, J.; Rauer, H.; Smith, A.; Tortora, C.; Van Eylen, V.; Winn, J. N.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 482:2(2019), pp. 1807-1823. [10.1093/mnras/sty2760]
K2-140b and K2-180b - Characterization of a hot Jupiter and a mini-Neptune from the K2 mission
Cusano F.;Napolitano N. R.;Smith A.;
2019
Abstract
We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-sized planet in an 8.9-d orbit transiting a V=12.6mag, metal-poor ([Fe/H] = -0.65 ± 0.10) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-d orbit around a V=12.6mag G6V ([Fe/H] = +0.10 ± 0.10) star in K2 campaign 10. Our results are based on K2 time-series photometry combined with high-spatial resolution imaging and high-precision radial velocity measurements. We present the first mass measurement of K2-180b. K2-180b has a mass of Mp = 11.3 ± 1.9M⊕ and a radius of Rp = 2.2 ± 0.1R⊕, yielding a mean density of ρp = 5.6 ± 1.9 g cm-3, suggesting a rocky composition. Given its radius, K2-180b is above the region of the so-called 'planetary radius gap'. K2-180b is in addition not only one of the densest mini-Neptune-sized planets, but also one of the few mini-Neptune-sized planets known to transit a metal-poor star. We also constrain the planetary and orbital parameters of K2-140b and show that, given the currently available Doppler measurements, the eccentricity is consistent with zero, contrary to the results of a previous study.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
