Probing early atmospheres

Probing Red Giant Atmospheres with Gravitational Microlensing

Gravitational microlensing provides a new technique for studying the surfaces of distant stars. Microlensing events are detected in real time and can be followed up with precision photometry and spectroscopy. This method is particularly adequate for studying red giants in the Galactic Bulge. We show that different properties of the stellar surface can be recovered from timedependent photometry ...

Probing Planetary Atmospheres with Stellar Occultations

Earth-based stellar occultations probe the temperature, pressure, and numberdensity profiles of planetary atmospheres in the microbar range with a vertical resolution of a few kilometers. Depending on the occultation data available for a given body and other information, the technique also allows determination of local density variations, extinction by aerosols and molecules, rotation period an...

Impact Generation of Methane-rich Atmospheres on Early Terrestrial Planets

Radiative Transfer in the Early Atmospheres of Mars and Earth

Introduction: The early climates of Earth and Mars appear to have been relatively warm, despite the existence of a less luminous young Sun [1]. Most attempts at reconciling these apparently contradicting observations rely on atmospheres that are richer in greenhouse gases (GHGs) than the present atmospheres of either planet [2]. The major contribution to most plausible greenhouses is from CO2 a...

Probing the Atmospheres of Planets Orbiting Microlensed Stars via Polarization Variability

We present a new method to identify and probe planetary companions of stars in the Galactic Bulge and Magellanic Clouds using gravitational microlensing. While spectroscopic studies of these planets is well beyond current observational techniques, monitoring polarization fluctuations during high magnification events induced by binary microlensing events will probe the composition of the planeta...