Astrobiology

The Late Veneer and Earth's habitability

Asteroid impacts were a hazard to any life on the Hadean Earth. A traditional approach to geochemical models of the asteroid impactors uses the concentration of highly siderophile elements including the Pt-group in the silicate Earth. These elements occur in roughly chondritic relative ratios, but with absolute concentrations <1% chondrite. This veneer component implies addition of chondrite-like material with 0.3-0.7% mass of the Earth’s mantle or an equivalent planet-wide thickness of 5-20 km. The veneer thickness, 200-300 m, within the lunar crust and mantle is much less.

Pluto's interacting surface and atmosphere

Pluto's main atmospheric species, N2, is also frozen on its surface, as are its minor atmospheric species, CH4 and CO. The New Horizons spacecraft found complicated and intriguing evidence for a dynamically interacting surface and atmosphere. The REX instrument shows a planetary boundary layer that depends on whether there's N2 ice available to sublimate.

Cancelled - Latest Exoplanet Results from NASA's Kepler/K2 Mission

The all-sky TESS mission will soon revolutionize our view of planets transiting the nearest, brightest stars to the Sun, just as the four-year survey by NASA's Kepler mission transformed our understanding of exoplanet demographics. Using the repurposed Kepler spacecraft, the ongoing K2 mission provides a natural transition from Kepler to TESS in terms of sky coverage, survey duration, and intensity of ground-based follow-up observations.

The History of the Martian South Polar Cap

In the last few years we have found that Mars' south polar cap has as much carbon-dioxide as Mars' current atmosphere. This raises numerous questions about how this massive deposit formed and what Mars was like when it was in the atmosphere. Using a combination of methods including spacecraft imagery, radar, and modeling we can start to answer some of these questions. Carver Bierson will discuss evidence that these deposits may have formed over several cycles of Mars atmosphere collapsing onto the surface and then sublimating back into the atmosphere.

Zombie vortices in protoplanetary disks & their roles in star and planet formation

The understanding of the early stages of planet formation from a disk of orbiting particles is an ongoing challenge for astrophysics and planetary science. Dr. Marcus will address the importance of instabilities in the particle disk as a link in the planetary formation chain.

A Terrestrial Exoplanet at Proxima Centauri

Dr. Anglada will discuss the new paper he is first author in reporting the presence of a 1.3 Earth mass exoplanet in a temperate orbit around Proxima Centauri. This finding was reported in Nature on Thursday 25 Aug 2016.
http://www.nature.com/nature/journal/v536/n7617/full/nature19106.html
Dr. Anglada will particpate remotely, and Dr. Franck Marchis of the SETI Institute will host a local panel to discuss the implications of the finding. "Our little world will never seem the same again".

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