TY - JOUR
T1 - Discovery and atmospheric characterization of giant planet Kepler-12b
T2 - An inflated radius outlier
AU - Fortney, J.J.
AU - Nutzman, P.
AU - Miller, N.
AU - Demory, B.-O.
AU - Seager, S.
AU - Désert, J.-M.
AU - Buchhave, L.A.
AU - Charbonneau, D.
AU - Fressin, F.
AU - Latham, D.W.
AU - Geary, J.C.
AU - Rowe, J.
AU - Caldwell, D.A.
AU - Jenkins, J.M.
AU - Christiansen, J.L.
AU - Marcy, G.W.
AU - Isaacson, H.
AU - Howard, A.
AU - Knutson, H.A.
AU - Buchhave, L.A.
AU - Ciardi, D.
AU - Gautier, T.N.
AU - Batalha, N.M.
AU - Bryson, S.T.
AU - Howell, S.B.
AU - Borucki, W.J.
AU - Koch, D.
AU - Lissauer, J.J.
AU - Haas, M.R.
AU - Everett, M.
AU - Deming, D.
AU - Brown, T.M.
AU - Ford, E.B.
AU - Gilliland, R.L.
AU - Fischer, D.A.
AU - Still, M.
AU - Lucas, P.W.
AU - Gillon, M.
N1 - ‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical Society
PY - 2011/11/1
Y1 - 2011/11/1
N2 - We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 R is among the handful of planets with super-inflated radii above 1.65 R. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 M planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 ± 0.010gcm. We detect the occultation of the planet at a significance of 3.7σ in the Kepler bandpass. This yields a geometric albedo of 0.14 ± 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7σ and 4σ in the 3.6 and 4.5 μm bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1σ) and e < 0.09 (3σ). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.
AB - We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 R is among the handful of planets with super-inflated radii above 1.65 R. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 M planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 ± 0.010gcm. We detect the occultation of the planet at a significance of 3.7σ in the Kepler bandpass. This yields a geometric albedo of 0.14 ± 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7σ and 4σ in the 3.6 and 4.5 μm bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1σ) and e < 0.09 (3σ). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.
KW - planets and satellites: atmospheres
KW - stars: individual (Kepler-12, KOI-20, KIC 11804465)
KW - techniques: spectroscopic
UR - http://www.scopus.com/inward/record.url?scp=80655144550&partnerID=8YFLogxK
U2 - 10.1088/0067-0049/197/1/9
DO - 10.1088/0067-0049/197/1/9
M3 - Article
AN - SCOPUS:80655144550
SN - 0067-0049
VL - 197
JO - Astrophysical Journal, Supplement Series
JF - Astrophysical Journal, Supplement Series
IS - 1
M1 - 9
ER -