Seminar Date:
Friday, May 23rd, 2014
3:15-4:15, Large Conference Room
Speaker:
Dr. Nick Cowan
CIERA - Northwestern University
Title:
Planetary Science from the Top-Down: the Exoplanet Opportunity
Abstract:
What started as a trickle in the mid 1990's is now a torrent, with over one thousand extrasolar planets currently known, and thousands of candidates awaiting confirmation. The study of exoplanets has already revolutionized our view of planet formation, and will soon do the same to our understanding of planetary atmospheres and interiors. The diversity of exoplanets gives us the leverage to crack hard problems in planetary science: cloud formation, atmospheric circulation, plate tectonics, etc. However, the characterization of exoplanets presents a challenge familiar to astronomers: our targets are so distant that we only see them as unresolved dots. I will describe how we can extract spatially-resolved snapshots of planets from such observations. These data are sufficient to constrain low-order climate models and therefore give us insight into the effects of clouds, heat transport, and geochemical cycling. Coarse measurements for a large number of planets is the perfect complement to the detailed measurements possible in the Solar System. That is the exoplanet opportunity.
Seminar Date:
Wednesday, March 12, 2014
Speaker:
Dr. Quinn Kanopacky
Dunlap Institute, Toronto
Title:
Orbits and Atmospheres of Directly Imaged Exoplanets
The first image of an extrasolar planetary system was obtained in 2008. Since then, there have been nearly a dozen gas giant planets directly imaged. These directly imaged exoplanets offer a new window into the rapidly evolving field of planet formation and evolution. The ability to separate the light of the planet from its host star is extremely advantageous for studying Jovian planetary atmospheres. The wide projected separations (~15 to 100 AU) of these planets provide insight into the orbital dynamics of long period objects. The combination of dynamical and atmospheric characterization can give clues about how these objects form and evolve. To demonstrate this new insight, I will discuss our team's results from an ongoing monitoring campaign of the HR 8799 directly imaged multi-planet system using the Keck Observatory adaptive optics system. High precision astrometry has provided constraints on the orbital properties of the four HR8799 planets. Moderate resolution spectroscopy has given precise estimates of the planets' effective temperature, surface gravity, and composition, leading to tantalizing clues about their formation. I will also discuss the successful first light runs of the Gemini Planet Imager (GPI), and instrument designed specifically to image and characterize young, widely separated Jovian planets. I will highlight some early results with GPI and describe the upcoming GPI Exoplanet Survey (GPIES), a three year campaign that will revolutionize our understanding of this fascinating planet population.
Seminar Date:
Monday, Jan 20th, 2014
Speaker:
Dr. Jenny Greene
Princeton University
Title:
To Build an Elliptical Galaxy
I discuss two essential aspects of elliptical galaxy formation: how they get their stars, and how they lose their gas. For the former, I use integral-field observations of local massive galaxies to study the stellar populations and kinematics of stars at large radius, to understand the origin of the size growth of elliptical galaxies.
Then I focus on black hole feedback as a means of clearing gas from massive galaxies. I show that luminous obscured quasars have ubiquitous, round ionized outflows with very high gas dispersions of nearly 1000 km/s out to 20 kpc.
Finally, if time permits I will combine these two themes and present our recent search for sub-pc supermassive black hole binaries.
Seminar Date:
November 7th, 2013
from 3:30-4:30 in the LCR
(Note the special date and time)
Speaker:
Dr. Jack Hewitt
NASA Goddard
Title:
Monsters of the Mid-plane: Galactic Accelerators in the Gamma-Ray Sky
