Updated Spitzer Emission Spectroscopy of Bright Transiting Hot Jupiter HD189733b

Abstract

We analyze all existing secondary eclipse time series spectroscopy of hot Jupiter HD189733b acquired with the now defunct Spitzer/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 to 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 6μm 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 relatively narrow wavelength range, between 5.5 and 7μm. This underscores the need for observational studies with broad wavelength coverage and high spectral resolution, in order to obtain robust information on exoplanet atmospheres.

16 pages, 13 figures and 3 tables. Accepted for publication in ApJ

References in corpus (18)

• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• Detection of Thermal Emission from an Extrasolar Planet
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• Line and Mean Opacities for Ultracool Dwarfs and Extrasolar Planets
• Tidal Evolution of Close-in Extra-Solar Planets
• Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres
• Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b
• Atmospheric Sulfur Photochemistry on Hot Jupiters
• The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b
• Strong Water Absorption in the Dayside Emission Spectrum of the Planet HD 189733b
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
• Hubble Space Telescope times-series photometry of the planetary transit of HD189733: no moon, no rings, starspots
• Strong Infrared Emission from the Extrasolar Planet HD189733b
• A Spectrum of an Extrasolar Planet
• Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b
• The Rotation Period of the Planet-Hosting Star HD 189733
• The mid-infrared spectrum of the transiting exoplanet HD 209458b

Cited by in corpus (8)

• Observing transiting planets with JWST -- Prime targets and their synthetic spectral observations
• Balancing the Energy Budget of Short-Period Giant Planets: Evidence for Reflective Clouds and Optical Absorbers
• Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
• Pressure-dependent water absorption cross sections for exoplanets and other atmospheres
• Quartz Clouds in the Dayside Atmosphere of the Quintessential Hot Jupiter HD 189733 b
• Ozone chemistry on tidally locked M dwarf planets
• The geometric albedo of the hot Jupiter HD 189733b measured with CHEOPS
• The Hubble/STIS Near-ultraviolet Transmission Spectrum of HD 189733b