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Astro Lunch Talks

Astro Lunch Talks
Wednesdays, 11:45am-1:00pm, 76-1275 Carlson Learning Center.
Topics will be emailed prior to the talk. Please contact Ben Sargent for more information. 
Upcoming Talks
Date/Time: April 16th, 12:30pm 76-1275
Speakers: Valerie Rapson
Title: A Spitzer and Herschel Study of the Protoplanetary Disk Around the Young Nearby System V4046 Sgr
Abstract: We present results from a spectroscopic Spitzer and Herschel mid-to-far-infrared study of the circumbinary disk orbiting V4046 Sgr. V4046 Sgr is a ~12 Myr-old spectroscopic binary that is still surrounded by, and is actively accreting from, a gaseous protoplanetary disk. The disk’s apparent longevity may be evidence for ongoing planet formation, or could be due to the influence of a distant tertiary (stellar) component. We report detections of emission lines of Ne II, Ar II, H2 and HCN in the Spitzer spectrum, as well as tentative detections of H2O and OH. The Herschel spectrum reveals emission from O I, OH, and, tentatively, high-J transitions of CO. Modeling of the silicate dust grains reveals that the inner disk is composed mainly of large amorphous pyroxine and olivine grains (85% by mass) and a small amount of crystalline silicates (15% by mass). These results are consistent with other lines of evidence indicating that planet building is ongoing in regions of the disk within ~30 AU of the central, close binary. We compare these results for V4046 Sgr to those for TW Hya, whose disk is similarly evolved but apparently orbits a single star. Combined with our previous and ongoing X-ray and radio studies of the V4046 Sgr system, the Spitzer and Herschel results will shed much-needed light on protoplanetary disk dissipation and planet formation processes in close binary systems.
Date Speaker Title
2/5/2014 David Merritt Planar satellite structures in the Local Group and their compatibility with ΛCDM
2/19/2014 Jennifer Connelly Challenging Groupthink: Global Properties and Population Exploration of X-ray & Optically Selected Groups at 0.1<z<0.8
3/5/2014 AST Panel Alternative Career Path Panel Discussion
3/19/2014 Davide Lena Gas kinematics within 300 pc from the nucleus of the Seyfert galaxy NGC 1386
4/10/2014 Beverly Berger Expanding $T^2$-Symmetric Vacuum Cosmological Spacetimes
4/16/2014 Valerie Rapson A Spitzer and Herschel Study of the Protoplanetary Disk Around the Young Nearby System V4046 Sgr
4/30/2014 TBA TBA
5/14/2014 TBA TBA

Past Talks

Date Speaker Title
12/4/2013 Joel Kastner & Marcus Freeman Some (Highly Biased) Highlights from the Asymmetrical Planetary Nebulae VI Conference: Planetary Nebula Shaping & X-rays
11/20/2013 Mihail Barbosu Dynamics of a Spacecraft in a Photo-Gravitational Field
10/23/2013 Jake Noel-Storr Communicating Astronomy with the Public
10/19/2013 Dave Principe Multiwavelength Observations of the Nearby, pre-Main Sequence Binary TWA 30
9/25/2013 Billy Vazquez NGC 6148, an AGN outside the Unified Scheme?
9/18/2013 Dmitry Vorobiev Polarimetry With Microgrid Polarizer Arrays:Simulation, Fabrication and Characterization of Polarization-Sensitive Focal Planes
9/11/2013 Christopher O'Dea The Labors of Hercules A: Trying to Make Sense of a Complicated Radio Galaxy
8/21/2013 Rudy Montez X-ray Emission from Central Stars of Planetary Nebulae: Surviving in a Photon Starved Environment
8/7/2013 Sravani Vaddi Overview of Astrostatics Workshop