Detection and characterization of an ultra-dense sub-Neptunian planet orbiting the Sun-like star K2-292
Alonso, R.; Deeg, H.; Erikson, A.; Fridlund, M.; Pätzold, M.; Rauer, H.; Nagel, E.; Amado, P. J.; Caballero, J. A.; Pallé, E.; Reiners, A.; Ribas, I.; Quirrenbach, A.; Guenther, E. W.; Kaminski, A.; Morales, J. C.; Lafarga, M.; Barragán, O.; Dai, F.; Gandolfi, D.; Hirano, T.; Korth, J.; Prieto-Arranz, J.; Nespral, D.; Hjorth, M.; Grziwa, S.; Albrecht, S.; Hatzes, A. P.; Csizmadia, Sz.; Smith, A. M. S.; Cabrera, J.; Narita, N.; Cochran, W. D.; Eigmüller, Ph.; Persson, C. M.; Van Eylen, V.; Nowak, G.; Winn, J. N.; Knudstrup, E.; Lund, M. N.; Esposito, M.; Lam, K. W. F.; Luque, R.; Redfield, S.; Mathur, S.; Bauer, F.; Fukui, A.; Hidalgo, D.; Justesen, A. B.; Endl, M.; Livingston, J.; Niraula, P.; Beck, P.; Montañes-Rodríguez, P.
Spain, United States, Germany, Japan, Italy, Sweden, Netherlands, Denmark
Abstract
We present the discovery and characterization of a new transiting planet from Campaign 17 of the Kepler extended mission K2. The planet K2-292 b is a warm sub-Neptune on a 17 day orbit around a bright (V = 9.9 mag) solar-like G3 V star with a mass and radius of M⋆ = 1.00 ± 0.03 M⊙ and R⋆ = 1.09 ± 0.03 R⊙, respectively. We modeled simultaneously the K2 photometry and CARMENES spectroscopic data and derived a radius of Rp=2.63-0.10+0.12 R⊕ and mass of Mp=24.5-4.4+4.4 M⊕, yielding a mean density of ρp=7.4-1.5+1.6 g cm-3, which makes it one of the densest sub-Neptunian planets known to date. We also detected a linear trend in the radial velocities of K2-292 (γ˙RV = -0.40-0.07+0.07 m s-1 d-1) that suggests a long-period companion with a minimum mass on the order of 33 M⊕. If confirmed, it would support a formation scenario of K2-292 b by migration caused by Kozai-Lidov oscillations.
The light curve is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/623/A114