TY - JOUR
T1 - Re-evaluating WASP-12b
T2 - Strong emission at 2.315 μm, deeper occultations, and an isothermal atmosphere
AU - Crossfield, Ian J.M.
AU - Barman, Travis
AU - Hansen, Brad M.S.
AU - Tanaka, Ichi
AU - Kodama, Tadayuki
PY - 2012/12/1
Y1 - 2012/12/1
N2 - We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 μm) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% ± 0.06%, corresponding to a brightness temperature of 3640 ± 230 K; second, recent Spitzer/Infrared Array Camera and Hubble Space Telescope/Wide Field Camera 3 observations; and third, a recently observed star only 1″ from WASP-12, which has diluted previous observations and which we further characterize here. We correct past WASP-12b eclipse measurements for the presence of this object, and we revisit the interpretation of WASP-12b's dilution-corrected emission spectrum. The resulting planetary emission spectrum is well approximated by a blackbody, and consequently our primary conclusion is that the planet's infrared photosphere is nearly isothermal. Thus, secondary eclipse spectroscopy is relatively ill suited to constrain WASP-12b's atmospheric abundances, and transmission spectroscopy may be necessary to achieve this goal.
AB - We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 μm) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% ± 0.06%, corresponding to a brightness temperature of 3640 ± 230 K; second, recent Spitzer/Infrared Array Camera and Hubble Space Telescope/Wide Field Camera 3 observations; and third, a recently observed star only 1″ from WASP-12, which has diluted previous observations and which we further characterize here. We correct past WASP-12b eclipse measurements for the presence of this object, and we revisit the interpretation of WASP-12b's dilution-corrected emission spectrum. The resulting planetary emission spectrum is well approximated by a blackbody, and consequently our primary conclusion is that the planet's infrared photosphere is nearly isothermal. Thus, secondary eclipse spectroscopy is relatively ill suited to constrain WASP-12b's atmospheric abundances, and transmission spectroscopy may be necessary to achieve this goal.
KW - eclipses
KW - infrared: planetary systems
KW - stars: individual (WASP-12, Bergfors-6)
KW - techniques: photometric
KW - techniques: spectroscopic
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U2 - 10.1088/0004-637X/760/2/140
DO - 10.1088/0004-637X/760/2/140
M3 - Article
AN - SCOPUS:84870288987
SN - 0004-637X
VL - 760
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 140
ER -