J/ApJ/649/1043 Transiting extrasolar planet HD 209458b (Richardson+, 2006)
A Spitzer(1) infrared radius for the transiting extrasolar planet HD 209458b.
Richardson L.J., Harrington J., Seager S., Deming D.
<Astrophys. J., 649, 1043-1047 (2006)>
=2006ApJ...649.1043R 2006ApJ...649.1043R
ADC_Keywords: Planets ; Photometry
Keywords: eclipses - infrared: general - stars: individual (HD 209458)
Abstract:
We have measured the infrared transit of the extrasolar planet
HD 209458b using the Spitzer Space Telescope. We observed two primary
eclipse events (one partial and one complete transit) using the 24um
array of the Multiband Imaging Photometer for Spitzer (MIPS). We
analyzed a total of 2392 individual images (10s integrations) of the
planetary system, recorded before, during, and after transit. We
performed optimal photometry on the images and used the local zodiacal
light as a short-term flux reference. At this long wavelength, the
transit curve has a simple boxlike shape, allowing robust solutions
for the stellar and planetary radii independent of stellar limb
darkening, which is negligible at 24um. We derive a stellar radius of
R*=(1.06±0.07)R☉, a planetary radius of Rp=(1.26±0.08)RJ,
and a stellar mass of 1.17M☉. Within the errors, our results
agree with the measurements at visible wavelengths. The 24um radius of
the planet therefore does not differ significantly compared to the
visible result. We point out the potential for deriving extrasolar
transiting planet radii to high accuracy using transit photometry at
slightly shorter IR wavelengths where greater photometric precision is
possible.
Description:
We observed two transit events using the Spitzer Space Telescope: a
half-eclipse event (ingress only) on 2004 December 5 and a
full-eclipse event on 2005 June 27. We used the MIPS 24um array, which
is a Si:As detector with 128x128pixels and an image scale of
2.55"/pixel. We obtained two series of 10s exposures using the
standard MIPS raster pattern, which places the star at 14 different
positions on the array. This produced 864 images during the
half-eclipse event and 1728 images during the full-eclipse event.
Objects:
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RA (2000) DE Designation(s)
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22 03 10.8 +18 53 04 HD 209458b = NAME Osiris
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 42 2392 Calibrated, unbinned photometry
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 F15.7 d HJD Time at start of observation
17- 24 F8.5 --- Phase Orbital phase
26- 33 F8.6 --- Int Relative intensity
35- 42 F8.6 --- e_Int rms uncertainty on Int
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 18-Jul-2008