Joint Astronomy/GeoSci Seminars: 2011

January 27, 2011 | 15:00, RI 480 | Host: Michael Gladders
The Small Star Opportunity to Find and Characterize Habitable Planets
Jacob Bean, Harvard University
One of the most exciting aspects of the field of exoplanets is the push towards the detailed study of habitable planets. Although most attention in this area is focused on Sun-like stars and has a time-horizon of decades, low-mass stars offer a real opportunity for the detection and atmospheric characterization of such planets in the near-future. I will describe work to overcome the technical challenges to making these kinds of observations for planetary systems around low-mass stars. I will also present results from two studies that utilize the power of low-mass stars: a planet search sensitive to potentially habitable planets and the first atmospheric characterization of a "super-earth" type planet. I will conclude with a look ahead at how similar observations with future instruments could yield the detection of biologically relevant molecules in the atmosphere of a potentially habitable planet around a low-mass star by the end of the decade.

February 3, 2011 | 15:00, Room 101, Hinds
Characterizing Super-Earths
Diana Valencia, Observatoire de la Cote d'Azur
Within the rapidly evolving field of exoplanets, super-Earths stand out as exceptional objects. They do not exist in our solar system, but they bear a relation to the terrestrial planets and icy satellites and thus constitute a new laboratory to test ideas. Remarkably, a subset of them may be habitable, making them interesting planets to characterize. In addition, the recent detections of the first three transiting low-mass planets mark the beginning of a prosperous field. The first generation of data arriving now is masses and radii, and in this context I will present results, challenges and future venues for inferring the composition and early evolution of these planets. Looking into the future, within the next decade we expect to have measurements of a coarse spectrum, which may provide a window into the understanding of the dynamics of the interior and thermal evolution of these potentially habitable planets.

February 10, 2011 | 15:00, RI 480 | Host: Michael Gladders
Seeing Other Solar Systems in the Making: Direct Imaging and Spectroscopy of Planets and Planet-Forming Disks
Thayne Currie, NASA-Goddard Space Flight Center
In this talk, I will describe new results on direct imaging and spectroscopy of young planets and planet-forming disks around other stars that provide a context for the evolution of the solar system's planets. First, I will discuss why direct imaging is both essential for characterizing planets around other stars and will explain the observing and image processing techniques that have proven successful for direct imaging. Second, I will present new science results from directly imaging gas giant planets around nearby, young stars, in particular the multi-planet system HR 8799. My data reveal a newly-detected, 4th planet orbiting at ~15 AU; my analysis shows that the HR 8799 planets have unique atmospheric properties, specifically thicker/denser clouds not found in other substellar objects and not predicted from standard atmosphere models. I will also present new detections of other young planets and images of planet-forming disks showing strong evidence for hitherto unseen planets. Starting next year, the Gemini Planet Imager instrument, with which I'm involved, will spatially resolve numerous planet-forming disks, provide a sensitive probe of the atmospheric evolution of over 100 soon-to-be imaged massive gas giants, and require facilities like Magellan for follow up. Finally, by the end of this decade, the University of Chicago-supported Giant Magellan Telescope will image and probe the atmospheric evolution of even lower-mass planets, potentially including young Earths.

February 17, 2011 | 15:00, RI 480
Observing Planet Formation in Nearby Circumstellar Disks
Lucas Cieza, Institute of Astronomy, University of Hawaii
Circumstellar disks are an integral part of the star formation process and the sites where planets are formed. Understanding their evolution is crucial for planet formation theory. Disks evolve through various physical processes, including accretion onto the star, grain growth and dust settling, dynamical interactions, and photoevaporation. In this talk, I will review our current understanding of the evolution of protoplanetary disks and the constraints they provide on planet formation processes. I will present results from our work on the so-called "transition" circumstellar disks, aiming to identify the sites of ongoing giant planet formation (i.e., the ultimate planet formation laboratories!). I will also discuss the prospects for detailed studies of these fascinating objects with the Atacama Large Millimeter Array (ALMA) as well as for the direct detection of forming planets with current and future instrumentation.

February 24, 2011 | 15:00, RI 480 | Host: Arieh Konigl
Planetary Systems from Kepler
Dan Fabrycky, UCO/Lick Observatory
On Feb. 2, the Kepler space mission released its first 4 months of data on all targets, as well as a series of papers on statistical results on transiting exoplanets. Perhaps the biggest surprise is the great abundance of candidate multiple-planet systems; out of 997 targets with a candidate transiting exoplanet, 170 of them hosted multiple candidates. I describe the dynamics (stability, transit timing variations) and architecture (resonances, inclinations) of these new planetary systems. Dynamics allows us to confirm that some of these systems are indeed planetary (Kepler-9, Kepler-11), and continued monitoring of these and other systems (the ultra-compact KOI-500, the coorbital KOI-730) will challenge and refine theories of the formation of planetary systems.