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Event Number 2112

  Friday, February 4th, 2011

Astronomy Colloquium
Special Astronomy Colloquium
Direct Imaging of Exoplanets: Prospects for comparative Exoplanetology
Time: 3:15 pm
Place: 4421 Sterling Hall
Speaker: Beth Biller, MPIA Heidelberg
Abstract: Direct detection, and direct spectroscopy in particular,
have great potential for advancing our understanding of extrasolar
planets. In combinations with other methods of planet detection,
direct imaging and spectroscopy will allow us to eventually: 1) fully map out the architecture of typical planetary systems and 2) study the physical properties of exoplanets (colors, temperatures, etc.) in depth. I will discuss initial results from the ongoing 500 hour NICI Planet-Finding Campaign using the novel Near-IR Coronagraphic Imager (NICI) at the 8-m Gemini South telescope. NICI combines a number of techniques to attenuate starlight a suppress superspeckles for direct detection of exoplanets: 1) Lyot coronagraphic imaging, 2) dual channel imaging for Spectral Differential Imaging (SDI) and 3)operation in a fixed Cassegrain rotator mode for Angular Differential Imaging (ADI). The combination of these techniques allows unprecedented contrasts of dmag > 14 (median value) at 1" in H band, sufficient to image giant planets (<5 MJup) around stars in nearby young moving groups and super jupiters (<10 MJup) around stars in the immediate solar neighborhood. I will also discuss the discovery of a tight substellar companion to the young solar analog PZ Tel(Biller et al. 2010), a member of the &#946; Pic moving group observed as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign.

PZ Tel B is one of the few young substellar companions
directly imaged at orbital separations similar to those of giant
planets in our own solar system.

Planetary mass companions to brown dwarfs are an important counterpart to planets around stars and provide key benchmark objects for evolutionary models of substellar objects. Therefore, I will also discuss results from a systematic Keck Laser Guide Star (LGS) adaptive optics search to directly image planetary mass companions to young brown dwarfs in the Upper Sco embedded cluster (Biller et al. 2011).
Host: Prof Amy Barger
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