[en] This paper reports the discovery and characterization of the transiting hot giant exoplanet Kepler-17b. The planet has an orbital period of 1.486 days, and radial velocity measurements from the Hobby-Eberly Telescope show a Doppler signal of 419.5[SUP]+13.3[/SUP] [SUB]-15.6[/SUB] m s[SUP]-1[/SUP]. From a transit-based estimate of the host star's mean density, combined with an estimate of the stellar effective temperature T [SUB]eff[/SUB] = 5630 ± 100 from high-resolution spectra, we infer a stellar host mass of 1.06 ± 0.07 M [SUB]&sun;[/SUB] and a stellar radius of 1.02 ± 0.03 R [SUB]&sun;[/SUB]. We estimate the planet mass and radius to be M [SUB]P[/SUB] = 2.45 ± 0.11 M [SUB]J[/SUB] and R [SUB]P[/SUB] = 1.31 ± 0.02 R [SUB]J[/SUB]. The host star is active, with dark spots that are frequently occulted by the planet. The continuous monitoring of the star reveals a stellar rotation period of 11.89 days, eight times the planet's orbital period; this period ratio produces stroboscopic effects on the occulted starspots. The temporal pattern of these spot-crossing events shows that the planet's orbit is prograde and the star's obliquity is smaller than 15°. We detected planetary occultations of Kepler-17b with both the Kepler and Spitzer Space Telescopes. We use these observations to constrain the eccentricity, e, and find that it is consistent with a circular orbit (e < 0.011). The brightness temperatures of the planet's infrared bandpasses are T_{3.6\, {\mu m}} = 1880 ± 100 K and T_{4.5\, {\mu m}} = 1770 ± 150 K. We measure the optical geometric albedo A[SUB]g[/SUB] in the Kepler bandpass and find A[SUB]g[/SUB] = 0.10 ± 0.02. The observations are best described by atmospheric models for which most of the incident energy is re-radiated away from the day side.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Désert, Jean*-Michel; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Charbonneau, David; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Demory, Brice*-Olivier; Massachusetts Institute of Technology, Cambridge, MA 02159, USA
Ballard, Sarah; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Carter, Joshua A; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Fortney, Jonathan J; Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
Cochran, William D; Department of Astronomy, University of Texas, Austin, USA
Endl, Michael; Department of Astronomy, University of Texas, Austin, USA
Quinn, Samuel N; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Isaacson, Howard T; Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA
Fressin, François; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Buchhave, Lars A; Neils Bohr Institute, University of Copenhagen, DK-2100 Denmark
Latham, David W; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Knutson, Heather A; Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA
Bryson, Stephen T; NASA Ames Research Center, Moffett Field, CA 94035, USA
Torres, Guillermo; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Rowe, Jason F; NASA Ames Research Center, Moffett Field, CA 94035, USA
Batalha, Natalie M; San Jose State University, San Jose, CA 95192, USA
Borucki, William J; NASA Ames Research Center, Moffett Field, CA 94035, USA
Brown, Timothy M; Las Cumbres Observatory Global Telescope, Goleta, CA 93117, USA
Caldwell, Douglas A; SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035, USA
Christiansen, Jessie L; NASA Ames Research Center, Moffett Field, CA 94035, USA
Deming, Drake; Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
Fabrycky, Daniel C; Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
Ford, Eric B; Department of Astronomy, University of Florida, Gainesville, FL 32611, USA
Gilliland, Ronald L; Space Telescope Science Institute, Baltimore, MD 21218, USA
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Haas, Michaël R; NASA Ames Research Center, Moffett Field, CA 94035, USA
Jenkins, Jon M; SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035, USA
Kinemuchi, Karen; Bay Area Environmental Research Inst./NASA Ames Research Center, Moffett Field, CA 94035, USA
Koch, David; NASA Ames Research Center, Moffett Field, CA 94035, USA
Lissauer, Jack J; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Lucas, Philip; Centre for Astrophyiscs Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK
Mullally, Fergal; SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035, USA
MacQueen, Phillip J; Department of Astronomy, University of Texas, Austin, USA
Marcy, Geoffrey W; Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA
Sasselov, Dimitar D; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Seager, Sara; Massachusetts Institute of Technology, Cambridge, MA 02159, USA
Still, Martin; Bay Area Environmental Research Inst./NASA Ames Research Center, Moffett Field, CA 94035, USA
Tenenbaum, Peter; SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035, USA
Uddin, Kamal; Orbital Sciences Corporation/NASA Ames Research Center, Moffett Field, CA 94035, USA
Winn, Joshua N; Massachusetts Institute of Technology, Cambridge, MA 02159, USA
