Date

Speaker

Title

Jan 23

Rory Barnes

University of Washington

(Tinsley Visiting Scholar: Planetary Group) "Long-Lived Chaotic Orbital Evolution of Exoplanets in Mean Motion Resonances with Mutual Inclinations"

abstract

Jan 30

John Scalo

University of Texas at Austin

Organizational Meeting.

Feb 6

No talk scheduled.

Feb 13

Monika Adamow

University of Texas at Austin

"Planets Around Giant Stars"

abstract

Feb 20

Adam Kraus

University of Texas at Austin

"The Impact of Stellar Multiplicity on Planetary Systems"

Feb 27

Trent Dupuy

University of Texas at Austin

"Substellar Fundamentals: New Dynamical Masses for Ultracool Dwarfs"

Mar 6

No talk scheduled.

Mar 13

No talk scheduled.

Mar 20

No talk scheduled. Spring Break: March 16-20.

Mar 27

Marshall C. Johnson

University of Texas at Austin

"Adventures in Doppler Tomography: Planet Validation, Nodal Precession, and Differential Rotation"

Apr 3

John Scalo

University of Texas at Austin

"Systematics of Molecular Cloud Linewidths over Three Orders of Magnitude in Linear Scale"

Apr 10

Neal Evans

University of Texas at Austin

"ALMA Observations of B335"

Apr 17

Andrew Helton

NASA/Ames: SOFIA

"SOFIA Science and Capabilities"

Apr 24

1) Benjamin T. Kidder

2) Raquel Martinez

University of Texas at Austin

1) "Angular Momentum Evolution of Young, Low-mass Stars"

2) "High-accuracy Spitzer/IRAC Subarray Photometry of Potential Warm Debris Disk Sources Discovered by WISE"

May 1

Yao-Lun Yang

University of Texas at Austin

2nd-Year Defense/Qualifying Exam Presentation: "The Structure of Class 0 Protostars: BHR71 in Herschel View"

We performed a comprehensive analysis to the Herschel spectra of BHR71, a embedded Class 0 protostar. We recover 66 lines in the central spaxel, and more than 700 lines detected in all spaxels in PACS, and SPIRE. The CO rotational diagram analysis shows three excitation temperature components, 32 K, 136 K, and 462 K. And low-J CO lines trace the outflow while the high-J CO lines are centered. The emissions of water traces the outflow in large scale, while water emissions populate along the equatorial plane in small scale. We model the structure of envelope using dust radiative transfer by Hyperion to fit the observed spectral energy distribution (SED) by Spitzer and Herschel. The model incorporates rotational collapse and outer static envelope as well as outflow cavity and disk. Our exploration of parameter space shows that the evolution of collapsing envelope can be constrained by Herschel spectra and the structure of outflow cavity plays a critical role in the shorter wavelength. We found the density profile of cavity with a power law with a constant inner region can reproduce the observations. The high central luminosity in the best-fit model shows a hint of a higher accretion rate than the rate derived from collapse model. Our model constrains BHR71 with the age of 30,000 years with the total gas mass of 3.75 Solar mass.

close

May 8

Emma Yu

University of Texas at Austin

"Using Multiple CO Isotopologues to Constrain the Vertical Turbulence Structure in Protoplanetary Disks"