Discovery and atmospheric characterization of giant planet Kepler-12b: An inflated radius outlier

Jonathan J. Fortney, Brice Olivier Demory, Jean Michel Désert, Jason Rowe, Geoffrey W. Marcy, Howard Isaacson, Lars A. Buchhave, David Ciardi, Thomas N. Gautier, Natalie M. Batalha, Douglas A. Caldwell, Stephen T. Bryson, Philip Nutzman, Jon M. Jenkins, Andrew Howard, David Charbonneau, Heather A. Knutson, Steve B. Howell, Mark Everett, François FressinDrake Deming, William J. Borucki, Timothy M. Brown, Eric B. Ford, Ronald L. Gilliland, David W. Latham, Neil Miller, Sara Seager, Debra A. Fischer, David Koch, Jack J. Lissauer, Michael R. Haas, Martin Still, Philip Lucas, Michael Gillon, Jessie L. Christiansen, John C. Geary

Research output: Contribution to journalArticle

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Abstract

We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 RJ is among the handful of planets with super-inflated radii above 1.65 RJ. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 MJ 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-3. 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.

Original languageEnglish (US)
Article number9
JournalAstrophysical Journal, Supplement Series
Volume197
Issue number1
DOIs
StatePublished - Nov 1 2011

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outlier
planets
planet
occultation
radii
heavy elements
Jupiter atmosphere
temperature inversions
temperature inversion
atmospheric models
multiple use
circular orbits
energy sources
opacity
albedo
inflation
Jupiter
photometry
physics
time measurement

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Fortney, J. J., Demory, B. O., Désert, J. M., Rowe, J., Marcy, G. W., Isaacson, H., ... Geary, J. C. (2011). Discovery and atmospheric characterization of giant planet Kepler-12b: An inflated radius outlier. Astrophysical Journal, Supplement Series, 197(1), [9]. https://doi.org/10.1088/0067-0049/197/1/9
Fortney, Jonathan J. ; Demory, Brice Olivier ; Désert, Jean Michel ; Rowe, Jason ; Marcy, Geoffrey W. ; Isaacson, Howard ; Buchhave, Lars A. ; Ciardi, David ; Gautier, Thomas N. ; Batalha, Natalie M. ; Caldwell, Douglas A. ; Bryson, Stephen T. ; Nutzman, Philip ; Jenkins, Jon M. ; Howard, Andrew ; Charbonneau, David ; Knutson, Heather A. ; Howell, Steve B. ; Everett, Mark ; Fressin, François ; Deming, Drake ; Borucki, William J. ; Brown, Timothy M. ; Ford, Eric B. ; Gilliland, Ronald L. ; Latham, David W. ; Miller, Neil ; Seager, Sara ; Fischer, Debra A. ; Koch, David ; Lissauer, Jack J. ; Haas, Michael R. ; Still, Martin ; Lucas, Philip ; Gillon, Michael ; Christiansen, Jessie L. ; Geary, John C. / Discovery and atmospheric characterization of giant planet Kepler-12b : An inflated radius outlier. In: Astrophysical Journal, Supplement Series. 2011 ; Vol. 197, No. 1.
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abstract = "We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 RJ is among the handful of planets with super-inflated radii above 1.65 RJ. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 MJ 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-3. 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.",
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Fortney, JJ, Demory, BO, Désert, JM, Rowe, J, Marcy, GW, Isaacson, H, Buchhave, LA, Ciardi, D, Gautier, TN, Batalha, NM, Caldwell, DA, Bryson, ST, Nutzman, P, Jenkins, JM, Howard, A, Charbonneau, D, Knutson, HA, Howell, SB, Everett, M, Fressin, F, Deming, D, Borucki, WJ, Brown, TM, Ford, EB, Gilliland, RL, Latham, DW, Miller, N, Seager, S, Fischer, DA, Koch, D, Lissauer, JJ, Haas, MR, Still, M, Lucas, P, Gillon, M, Christiansen, JL & Geary, JC 2011, 'Discovery and atmospheric characterization of giant planet Kepler-12b: An inflated radius outlier', Astrophysical Journal, Supplement Series, vol. 197, no. 1, 9. https://doi.org/10.1088/0067-0049/197/1/9

Discovery and atmospheric characterization of giant planet Kepler-12b : An inflated radius outlier. / Fortney, Jonathan J.; Demory, Brice Olivier; Désert, Jean Michel; Rowe, Jason; Marcy, Geoffrey W.; Isaacson, Howard; Buchhave, Lars A.; Ciardi, David; Gautier, Thomas N.; Batalha, Natalie M.; Caldwell, Douglas A.; Bryson, Stephen T.; Nutzman, Philip; Jenkins, Jon M.; Howard, Andrew; Charbonneau, David; Knutson, Heather A.; Howell, Steve B.; Everett, Mark; Fressin, François; Deming, Drake; Borucki, William J.; Brown, Timothy M.; Ford, Eric B.; Gilliland, Ronald L.; Latham, David W.; Miller, Neil; Seager, Sara; Fischer, Debra A.; Koch, David; Lissauer, Jack J.; Haas, Michael R.; Still, Martin; Lucas, Philip; Gillon, Michael; Christiansen, Jessie L.; Geary, John C.

In: Astrophysical Journal, Supplement Series, Vol. 197, No. 1, 9, 01.11.2011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Discovery and atmospheric characterization of giant planet Kepler-12b

T2 - An inflated radius outlier

AU - Fortney, Jonathan J.

AU - Demory, Brice Olivier

AU - Désert, Jean Michel

AU - Rowe, Jason

AU - Marcy, Geoffrey W.

AU - Isaacson, Howard

AU - Buchhave, Lars A.

AU - Ciardi, David

AU - Gautier, Thomas N.

AU - Batalha, Natalie M.

AU - Caldwell, Douglas A.

AU - Bryson, Stephen T.

AU - Nutzman, Philip

AU - Jenkins, Jon M.

AU - Howard, Andrew

AU - Charbonneau, David

AU - Knutson, Heather A.

AU - Howell, Steve B.

AU - Everett, Mark

AU - Fressin, François

AU - Deming, Drake

AU - Borucki, William J.

AU - Brown, Timothy M.

AU - Ford, Eric B.

AU - Gilliland, Ronald L.

AU - Latham, David W.

AU - Miller, Neil

AU - Seager, Sara

AU - Fischer, Debra A.

AU - Koch, David

AU - Lissauer, Jack J.

AU - Haas, Michael R.

AU - Still, Martin

AU - Lucas, Philip

AU - Gillon, Michael

AU - Christiansen, Jessie L.

AU - Geary, John C.

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 RJ is among the handful of planets with super-inflated radii above 1.65 RJ. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 MJ 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-3. 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 RJ is among the handful of planets with super-inflated radii above 1.65 RJ. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 MJ 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-3. 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.

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