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"

Studies of exoplanets in mean motion resonance typically assume the orbits are coplanar. If this assumption is relaxed, then the planets can evolve chaotically, but still persist for at least 10 Gyr. A wide range of behavior is possible, from fast, low amplitude variations to systems in which eccentricities reach 0.9999 and inclinations 179.9 degrees. While the orbital elements evolve chaotically, at least one resonant argument always librates. If non-planar, the HD 73526, HD 45364 and HD 60532 systems may be in chaotically-evolving resonances. Chaotic evolution is apparent in the 2:1, 3:1 and 3:2 resonances, and for planetary masses from lunar- to Jupiter-mass. In some cases, orbital disruption occurs after several Gyr, implying the mechanism is not rigorously stable, just long-lived relative to the main sequence lifetimes of solar-type stars. Planet-planet scattering appears to yield planets in inclined resonances that evolve chaotically in about 0.5% of cases. These results suggest that 1) approximate methods for identifying unstable orbital architectures may have limited applicability, 2) the observed close-in exoplanets may be produced during the high eccentricity phases induced by inclined resonances, 3) those exoplanets' orbital planes may be misaligned with the host star's spin axis, 4) systems with resonances may be systematically younger than those without, 5) the distribution of period ratios of adjacent planets detected via transit may be skewed due to inclined resonances, and 6) potentially habitable planets in resonances may have dramatically different climatic evolution than the Earth. The GAIA spacecraft is capable of discovering giant planets in these types of orbits.

close

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"

abstract

May 8

Emma Yu

University of Texas at Austin

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