Portal de Periódicos da CAPES

K2-260 b: a hot Jupiter transiting an F star, and K2-261 b: a warm Saturn around a bright G star

2018; Oxford University Press; Volume: 481; Issue: 1 Linguagem: Inglês

10.1093/mnras/sty2238

1365-2966

Marshall C. Johnson, F. Dai, A. B. Justesen, D. Gandolfi, A. P. Hatzes, G. Nowak, Michael Endl, William D. Cochran, D. Hidalgo, Noriharu Watanabe, H. Parviainen, Teruyuki Hirano, Steven Villanueva, J. Prieto-Arranz, Norio Narita, Ε. Πάλλη, E. W. Guenther, Oscar Barragán, T. Trifonov, Prajwal Niraula, Phillip J. MacQueen, J. Cabrera, Sz. Csizmadia, Philipp Eigmüller, S. Grziwa, J. Korth, M. Pätzold, A. M. S. Smith, Simon Albrecht, R. Alonso, H. J. Deeg, A. Erikson, M. Esposito, M. Fridlund, Akihiko Fukui, Nobuhiko Kusakabe, Masayuki Kuzuhara, John H. Livingston, P. Montañés‐Rodríguez, D. Nespral, C. M. Persson, T. Purismo, S. I. Raimundo, H. Rauer, I. Ribas, Motohide Tamura, Vincent Van Eylen, Joshua N. Winn,

Gamma-ray bursts and supernovae

We present the discovery and confirmation of two new transiting giant planets from the Kepler extended mission K2. K2-260 b is a hot Jupiter transiting a $V=12.7$ F6V star in K2 Field 13, with a mass and radius of $M_{\star}=1.39_{-0.06}^{+0.05} M_{\odot}$ and $R_{\star}=1.69 \pm 0.03 R_{\odot}$. The planet has an orbital period of $P=2.627$ days, and a mass and radius of $M_P=1.42^{+0.31}_{-0.32} M_J$ and $R_P=1.552^{+0.048}_{-0.057} R_J$. This is the first K2 hot Jupiter with a detected secondary eclipse in the Kepler bandpass, with a depth of $71 \pm 15$ ppm, which we use to estimate a geometric albedo of $A_g\sim0.2$. We also detected a candidate stellar companion at 0.6" from K2-260; we find that it is very likely physically associated with the system, in which case it would be an M5-6V star at a projected separation of $\sim400$ AU. K2-261 b is a warm Saturn transiting a bright ($V=10.5$) G7IV/V star in K2 Field 14. The host star is a metal-rich ([Fe/H]$=0.36 \pm 0.06$), mildly evolved $1.10_{-0.02}^{+0.01} M_{\odot}$ star with $R_{\star}=1.65 \pm 0.04 R_{\odot}$. Thanks to its location near the main sequence turn-off, we can measure a relatively precise age of $8.8_{-0.3}^{+0.4}$ Gyr. The planet has $P=11.633$ days, $M_P=0.223 \pm 0.031 M_J$, and $R_P=0.850^{+0.026}_{-0.022} R_J$, and its orbit is eccentric ($e=0.39 \pm 0.15$). Its brightness and relatively large transit depth make this one of the best known warm Saturns for follow-up observations to further characterize the planetary system.