A Spitzer Search for Water in the Transiting Exoplanet HD189733b
arXiv:0709.0576 · doi:10.1086/522792
Abstract
We present Spitzer Space Telescope observations of the extrasolar planet HD189733b primary transit, obtained simultaneously at 3.6 and 5.8 microns with the Infrared Array Camera. The system parameters, including planetary radius, stellar radius, and impact parameter are derived from fits to the transit light curves at both wavelengths. We measure two consistent planet-to-star radius ratios, (Rp/Rs)[3.6m] = 0.1560 +/- 0.0008(stat) +/- 0.0002(syst) and (Rp/Rs)[5.8m] = 0.1541 +/- 0.0009(stat) +/- 0.0009(syst), which include both the random and systematic errors in the transit baseline. Although planet radii are determined at 1%-accuracy, if all uncertainties are taken into account the resulting error bars are still too large to allow for the detection of atmospheric constituants like water vapour. This illustrates the need to observe multiple transits with the longest possible out-of-transit baseline, in order to achieve the precision required by transmission spectroscopy of giant extrasolar planets.
Accepted in The Astrophysical Journal Letters
References in corpus (9)
- Using Stellar Limb-Darkening to Refine the Properties of HD 209458b
- Hubble Space Telescope times-series photometry of the planetary transit of HD189733: no moon, no rings, starspots
- The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
- Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b
- A Sensitive Search for Variability in Late L Dwarfs: The Quest for Weather
- Infrared Transmission Spectra for Extrasolar Giant Planets
- Analysis of Spitzer Spectra of Irradiated Planets: Evidence for Water Vapor?
- Refined parameters of the planet orbiting HD 189733
- A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD209458b
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- Atmospheric Circulation of Hot Jupiters: A Shallow Three-Dimensional Model
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