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Project Progress

This task encompasses remote-sensing observations of Solar System and extrasolar planets made by the VPL team. These observations, while providing scientific exploration in its own right, also allow us to test our planetary models and help advance techniques to retrieve information from the astronomical data that we obtain

This year we made and/or analyzed observations of Mars, Venus and Earth taken by ground-based and spaceborne observatories, to better understand how well we can determine planetary properties like atmospheric and surface temperature and pressure, when a terrestrial planet is observed only as a distant point of light.

This year we completed our collaboration with the EPOXI team, with a final publication of the Earth dataset (Livengood et al., 2011). However, we continue to analyze near-infrared EPOXI spectra of the Earth and Mars to determine the likely error in temperature and surface reflectivity retrieval for disk-integrated Mars and Earth data, and to also explore a novel way of determining surface pressure for Earth-like atmospheres (Schwieterman, 2012, in prep). We also used our radiative transfer model to generate transmission spectra of Earth-like planets with a range of atmospheric pressures and for different oxygen abundances. We have used these simulations to show that simultaneous measurements of the absorption features from the O₂-O₂ dimer molecule and molecular oxygen (O₂) can be used as a new technique to probe planetary atmospheric pressure for oxygenated atmospheres (Misra et al., 2012, in prep). Robinson and Meadows also made conference presentations on detecting exomoons using spectroscopy of the host planet, and concepts for an L1 Earth observing mission for astrobiology (Robinson et al., 2011; Meadows and Robinson, 2011).

We have also analyzed near-infrared observations of Venus taken with the Apache Point Observatory 3.5m telescope, and the Anglo Australian 3.9m telescope. We were able to show that night side emission may be detected in the disk-average of a Venus-like planet, if observed at optimal phase, an that this emission would reveal that the planet was unlikely to have a habitable surface temperature (Arney et al., 2012a,b). Using the AAT Venus dataset we investigated the distribution of carbon monoxide in the lower atmosphere of Venus using observation of the 2.3um band. The spatial distribution of CO mapped appears to show a strong Hadley-cell (Cotton et al., 2011).

Bailey, Agol, Barnes, Raymond and collaborators continued their work searching for extrasolar terrestrial planets using radial velocity surveys and Kepler data (e.g. Fleming et al., 2012; Wisniewski et al., 2012; Anglada-Escude et al., 2012).