Fritz Benedict (U. Texas, Austin)
Astrometry with the Hubble Space Telescope In a few years astrometry with the Fine Guidance Sensors on Hubble
Space Telescope will be replaced by SIM, GAIA, and long-baseline
interferometry. Until then we remain a resource of choice for sub-millisecond
of arc precision optical astrometry. As examples I discuss 1) the uses
which can be made of our parallaxes of galactic Cepheids, and 2) the
determination of perturbation orbital elements for several exoplanet
host stars, yielding true companion masses. Future results will include
a calibration of the Pop II Period-Luminosity relation and tests of
exoplanetary system coplanarity.
Brett Gladman (Univ. of British Columbia)
Resonant dynamics of Kuiper Belt objects and induced biases in surveys
Kathryn Johnston (Columbia Univ.)
Telling Tales with Tidal Tails The distributions of stars in the different components of galaxies
are broadly described in terms of analytic density and velocity distributions
functions that are constructed to be in equilibrium with the underlying
potential. In the last decade, the stellar halos of the Milky Way and
Andromeda galaxies have been mapped in exquisite detail, revealing that
they are actually richly substructured in phase-space due to the presence
of debris from tidally disrupted satellites. These observations are
qualitatively consistent with our expectations for large galaxies formed
hierarchically from smaller galaxies, but are they actually telling us
anything more quantifiable? In this talk I will review the origin of
these substructures and discuss what they can tell us about the history
and total mass distributions of these galaxies.
Frederic Masset (Commissariat a` l'e'nergie atomique - Saclay and IA-UNAM, Mexico City)
The co-orbital corotation torque and its effect on planet migration A planet embedded in a gaseous protoplanetary disk is subject to a
tidal torque from the disk. When the orbit is circular, the co-orbital
corotation torque corresponds to the torque arising from the material of
the coorbital region. I will present the dynamics of this region, and I
will present situations in which the co-orbital corotation torque plays
a major role for planetary migration. Namely I will show how this torque
can halt the migration of low-mass planets at the edge of a cavity, then
I will turn to the case of sub-giant planets embedded in massive disks,
for which migration can undergo a runaway. Finally, I will present some
recent results about the properties of the co-orbital corotation torque
in a radiatively inefficient disk, and I will show how the latter can halt
or revert type I migration.
David Nesvorny (SwRI)
Analytic Theory of the YORP Effect for Near-Spherical Objects The YORP effect is produced when the surface of a small object in the
interplanetary space is heated by sunlight and re-radiates the absorbed
energy in thermal wavelengths. The absorbed, reflected and emitted photons
produce tiny torques on the small body which can change its spin rate and
obliquity over planetary timescales. Previous theories of the YORP effect
relied on numerical or semi-numerical evaluation of the radiation torques.
Here we develop an alternative approach and calculate the YORP torques
analytically. Our theory is limited to near-spherical objects. While
unsuitable for a precise determination of torques on elongated and/or
highly-irregular objects, the analytic theory helps to explain several
general properties of the YORP torques that were identified in previous
numerical works. We discuss applications of the analytic theory on
near-spherical asteroids like 1998 KY$_{26}$ and on more elongated
and/or irregular objects like (1862) Apollo and (25143) Itokawa.
Doug Richstone (U. Michigan)
Black Holes and the Evolution of Galaxies
Brouwer Award Lecture: Dr. Simon D. M. White (MPI fu"r Astrophysik) is the winner of the
2008 Brouwer Award. He will present the following prize lecture:
Very small-scale structure in the Cold Dark Matter distribution. Cold Dark Matter is apparently the dominant component of all
structures larger than individual galaxies. Simulations of cosmic
evolution predict that its distribution should show a very rich
nonlinear structure which agrees with much (but not all) of the
available observational information. Techniques for direct detection
of Cold Dark Matter in cooled bolometers (for neutralinos) and
resonant cavities (for axions) have advanced to the point where a
positive result is within reach. In addition, the next generation of
gamma-ray telescopes will be sensitive enough to detect annihilation
radiation from many plausible kinds of neutralino. In all these cases,
the signal to be detected depends sensitively on how the dark matter
distribution is structured on meter scales or smaller. Such scales
are many orders of magnitude below those that can be studied with
conventional N-body methods. I will describe new techniques which may
allow these issues to be addressed through simulations of evolution
from fully general CDM initial conditions.
Public Lecture: Carolyn Porco (Space Science Inst.) will give the always-popular
public talk entitled "At Saturn: Tripping the Flight Fantastic", in
which she will highlight the most dramatic and significant results
from Cassini's exploration of the Saturn system.
