THE HOT-JUPITER KEPLER-17b: DISCOVERY, OBLIQUITY FROM STROBOSCOPIC STARSPOTS, AND ATMOSPHERIC CHARACTERIZATION

Journal Article · Tue Nov 01 04:00:00 EDT 2011 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/197/1/14· OSTI ID:22047342

Desert, Jean-Michel; Charbonneau, David; Ballard, Sarah; Carter, Joshua A; Quinn, Samuel N; Fressin, Francois; Latham, David W; Torres, Guillermo ^[1]; Demory, Brice-Olivier ^[2]; Fortney, Jonathan J ^[3]; Cochran, William D; Endl, Michael ^[4]; Isaacson, Howard T; Knutson, Heather A ^[5]; Buchhave, Lars A ^[6]; Bryson, Stephen T; Rowe, Jason F; Borucki, William J ^[7]; Batalha, Natalie M ^[8]; others, and

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Massachusetts Institute of Technology, Cambridge, MA 02159 (United States)
3. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
4. Department of Astronomy, University of Texas, Austin (United States)
5. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
6. Neils Bohr Institute, University of Copenhagen, DK-2100 Denmark (Denmark)
7. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
8. 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, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 1 Vol. 197; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALBEDO
ASTRONOMY
ASTROPHYSICS
BRIGHTNESS
DENSITY
DOPPLER EFFECT
ECLIPSE
MASS
ORBITS
PLANETS
RADIAL VELOCITY
ROTATION
STARS
STARSPOTS
TELESCOPES