THE HOT-JUPITER KEPLER-17b: DISCOVERY, OBLIQUITY FROM STROBOSCOPIC STARSPOTS, AND ATMOSPHERIC CHARACTERIZATION
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Massachusetts Institute of Technology, Cambridge, MA 02159 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
- Department of Astronomy, University of Texas, Austin (United States)
- Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
- Neils Bohr Institute, University of Copenhagen, DK-2100 Denmark (Denmark)
- NASA Ames Research Center, Moffett Field, CA 94035 (United States)
- San Jose State University, San Jose, CA 95192 (United States)
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}{sub -15.6} m s{sup -1}. From a transit-based estimate of the host star's mean density, combined with an estimate of the stellar effective temperature T{sub eff} = 5630 {+-} 100 from high-resolution spectra, we infer a stellar host mass of 1.06 {+-} 0.07 M{sub Sun} and a stellar radius of 1.02 {+-} 0.03 R{sub Sun }. We estimate the planet mass and radius to be M{sub P} = 2.45 {+-} 0.11 M{sub J} and R{sub P} = 1.31 {+-} 0.02 R{sub J}. 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 Degree-Sign . 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{sub 3.6{mu}m} = 1880 {+-} 100 K and T{sub 4.5{mu}m} = 1770 {+-} 150 K. We measure the optical geometric albedo A{sub g} in the Kepler bandpass and find A{sub g} = 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.
- OSTI ID:
- 22047342
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 197, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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