Abstract
We analyze all existing secondary eclipse time series spectroscopy of hot Jupiter HD 189733b acquired with the now defunct Spitzer/Infrared Spectrograph (IRS) instrument. We describe the novel approaches we develop to remove the systematic effects and extract accurate secondary eclipse depths as a function of wavelength in order to construct the emission spectrum of the exoplanet. We compare our results with a previous study by Grillmair et al. that did not examine all data sets available to us. We are able to confirm the detection of a water feature near 6 μm claimed by Grillmair et al. We compare the planetary emission spectrum to three model families - based on isothermal atmosphere, gray atmosphere, and two realizations of the complex radiative transfer model by Burrows et al.; adopted in Grillmair et al.'s study. While we are able to reject the simple isothermal and gray models based on the data at the 97% level just from the IRS data, these rejections hinge on eclipses measured within a relatively narrow wavelength range, between 5.5 and 7 μm. This underscores the need for observational studies with broad wavelength coverage and high spectral resolution, in order to obtain robust information on exoplanet atmospheres.
Original language | English (US) |
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Article number | 100 |
Journal | Astrophysical Journal |
Volume | 796 |
Issue number | 2 |
DOIs | |
State | Published - Dec 1 2014 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- eclipses
- planetary systems
- techniques: spectroscopic