J/A+A/511/A3 Light curves of CoRoT-2 in z-band, 4.5um and 8um (Gillon+, 2010)
The thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8um.
Gillon M., Lanotte A.A., Barman T., Miller N., Demory B.-O., Deleuil M.,
Montalban J., Bouchy F., Collier Cameron A., Deeg H.J., Fortney J.J.,
Fridlund M., Harrington J., Magain P., Moutou C., Queloz D., Rauer H.,
Rouan D., Schneider J.
<Astron. Astrophys. 511, A3 (2010)>
=2010A&A...511A...3G 2010A&A...511A...3G
ADC_Keywords: Binaries, eclipsing ; Planets ; Magnitudes
Keywords: binaries: eclipsing - planetary systems - stars: individual: CoRoT-2 -
techniques: photometric
Abstract:
We report measurements of the thermal emission of the young and
massive planet CoRoT-2b at 4.5 and 8um with the Spitzer Infrared
Array Camera (IRAC). Our measured occultation depths are
0.510±0.042% at 4.5 and 0.41±0.11% at 8um. In addition to
the CoRoT optical measurements, these planet/star flux ratios indicate
a poor heat distribution on the night side of the planet and agree
better with an atmosphere free of temperature inversion layer. Still,
such an inversion is not definitely ruled out by the observations and
a larger wavelength coverage is required to remove the current
ambiguity. Our global analysis of CoRoT, Spitzer, and ground-based
data confirms the high mass and large size of the planet with slightly
revised values (Mp=3.47±0.22MJ, Rp=1.466±0.044 RJ). We
find a small but significant offset in the timing of the occultation
when compared to a purely circular orbital solution, leading to
e*cos(omega)=-0.00291±0.00063 where e is the orbital eccentricity
and omega is the argument of periastron. Constraining the age of the
system to at most a few hundred Myr and assuming that the non-zero
orbital eccentricity does not come from a third undetected body, we
modeled the coupled orbital-tidal evolution of the system with various
tidal Q values, core sizes, and initial orbital parameters. For
Qs'=105-106, our modeling is able to explain the large radius of
CoRoT-2b if Qp'≤105.5 through a transient tidal circularization
and corresponding planet tidal heating event. Under this model, the
planet will reach its Roche limit within 20Myr at most.
Description:
Photometric time series obtained for CoRoT-2 with the VLT/FORS2 camera
in z band during a transit of the planet CoRoT-2b and with the
SST/IRAC camera at 4.5 and 8um during an occultation of the same
planet.
Objects:
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RA (2000) DE Designation(s)
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19 27 06.5 +01 23 01 CoRoT-2 = GSC 00465-01282
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
forsz.dat 45 399 VLT/FORS2 photometric time series
iracch2.dat 101 865 IRAC 4.5um photometric time series
iracch4.dat 63 1348 IRAC 8um photometric time series
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See also:
B/corot : CoRoT observation log Release 4 (CoRoT, 2009)
Byte-by-byte Description of file: forsz.dat
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Bytes Format Units Label Explanations
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1- 15 F15.7 d HJD Heliocentric Julian Date
17- 25 F9.7 --- Flux Flux in z-band
27- 35 F9.7 --- e_Flux Error on flux
37- 45 F9.7 --- Airmass Airmass
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Byte-by-byte Description of file: iracch2.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d HJD Heliocentric Julian Date
20- 38 F19.17 --- Flux Flux at 4.5um
40- 63 E24.18 --- e_Flux Error on Flux
65- 82 F18.14 pix Xpos X-position of the PSF centroid on the chip
84-101 F18.14 pix Ypos Y-position of the PSF centroid on the chip
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Byte-by-byte Description of file: iracch4.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d HJD Heliocentric Julian Date
20- 38 F19.17 --- Flux Flux at 8um
40- 63 E24.18 --- e_Flux Error on Flux
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Acknowledgements:
Michael Gillon,
(End) Patricia Vannier [CDS] 29-Dec-2009