K2-280b -- a low density warm sub-Saturn around a mildly evolved star

Autor: Nowak, Grzegorz, Palle, Enric, Gandolfi, Davide, Deeg, Hans J., Hirano, Teruyuki, Barragán, Oscar, Kuzuhara, Masayuki, Dai, Fei, Luque, Rafael, Persson, Carina M., Fridlund, Malcolm, Johnson, Marshall C., Korth, Judith, Livingston, John H., Grziwa, Sascha, Mathur, Savita, Hatzes, Artie P., Prieto-Arranz, Jorge, Nespral, David, Hidalgo, Diego, Hjorth, Maria, Albrecht, Simon, Van Eylen, Vincent, Lam, Kristine W. F., Cochran, William D., Esposito, Massimiliano, Csizmadia, Szilárd, Guenther, Eike W., Kabath, Petr, Blay, Pere, Brahm, Rafael, Jordán, Andrés, Espinoza, Néstor, Rojas, Felipe, Barris, Núria Casasayas, Rodler, Florian, Sobrino, Roi Alonso, Cabrera, Juan, Carleo, Ilaria, Chaushev, Alexander, de Leon, Jerome, Eigmüller, Philipp, Endl, Michael, Erikson, Anders, Fukui, Akihiko, Georgieva, Iskra, González-Cuesta, Lucía, Knudstrup, Emil, Lund, Mikkel N., Rodríguez, Pilar Montañes, Murgas, Felipe, Narita, Norio, Niraula, Prajwal, Pätzold, Martin, Rauer, Heike, Redfield, Seth, Ribas, Ignasi, Skarka, Marek, Smith, Alexis M. S., Subjak, Jano
Rok vydání: 2020
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1093/mnras/staa2077
Popis: We present an independent discovery and detailed characterisation of K2-280b, a transiting low density warm sub-Saturn in a 19.9-day moderately eccentric orbit (e = 0.35_{-0.04}^{+0.05}) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280b has a radius of R_b = 7.50 +/- 0.44 R_Earth and a mass of M_b = 37.1 +/- 5.6 M_Earth, yielding a mean density of 0.48_{-0.10}^{+0.13} g/cm^3. The host star is a mildly evolved G7 star with an effective temperature of T_{eff} = 5500 +/- 100 K, a surface gravity of log(g) = 4.21 +/- 0.05 (cgs), and an iron abundance of [Fe/H] = 0.33 +/- 0.08 dex, and with an inferred mass of M_star = 1.03 +/- 0.03 M_sun and a radius of R_star = 1.28 +/- 0.07 R_sun. We discuss the importance of K2-280b for testing formation scenarios of sub-Saturn planets and the current sample of this intriguing group of planets that are absent in the Solar System.
Comment: 14 pages, 9 figures, 5 tables, accepted for publication in MNRAS
Databáze: arXiv
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