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Biosignatures from Earth-like planets around M dwarfs.
Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs to determine which biosignature gases might be observed by a future, space-based telescope.
The presence of methane in the atmosphere of an extrasolar planet
A near-infrared transmission spectrum of the planet HD 189733b that shows the presence of methane is reported, and a resolved water vapour band at 1.9 μm confirms the recent claim of water in this object.
Spectral signatures of photosynthesis. II. Coevolution with other stars and the atmosphere on extrasolar worlds.
M star planets could be a half to a tenth as productive as Earth in the visible, but exceed Earth if useful photons extend to 1.1 microm for anoxygenic photosynthesis, and under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth.
Water vapour in the atmosphere of a transiting extrasolar planet
An analysis of recent observations of the hot Jupiter HD 189733b taken during the transit, when the planet passed in front of its parent star, finds that absorption by water vapour is the most likely cause of the wavelength-dependent variations in the effective radius of the planet.
MOLECULAR SIGNATURES IN THE NEAR-INFRARED DAYSIDE SPECTRUM OF HD 189733b
We have measured the dayside spectrum of HD 189733b between 1.5 and 2.5 μm using the NICMOS instrument on the Hubble Space Telescope. The emergent spectrum contains significant modulation, which we…
Detectability of planetary characteristics in disk-averaged spectra. I: The Earth model.
A spatially and spectrally resolved model of the Earth is developed and comparison between the data and model indicates that several atmospheric species can be identified in disk-averaged Earth spectra, and potentially detected depending on the wavelength range and resolving power of the instrument.
A Population Study of Gaseous Exoplanets
We present here the analysis of 30 gaseous extrasolar planets, with temperatures between 600 and 2400 K and radii between 0.35 and 1.9 R Jup. The quality of the HST/WFC3 spatially scanned data…
Detection of an atmosphere around the super-Earth 55 Cancri e
We report the analysis of two new spectroscopic observations of the super-Earth 55 Cancri e, in the near infrared, obtained with the WFC3 camera onboard the HST. 55 Cancri e orbits so close to its…
Detectability of planetary characteristics in disk-averaged spectra II: synthetic spectra and light-curves of earth.
Modeling the disk-averaged sensitivity to the "red-edge," a distinctive spectral signature of vegetation, showed that Earth's land vegetation could be seen in disk-aversaged spectra, even with cloud cover, when the signal was averaged over the daily time scale.
WATER, METHANE, AND CARBON DIOXIDE PRESENT IN THE DAYSIDE SPECTRUM OF THE EXOPLANET HD 209458b
Using the NICMOS instrument on the Hubble Space Telescope, we have measured the dayside spectrum of HD 209458b between 1.5 and 2.5 μm. The emergent spectrum is dominated by features due to the…