Brian's Home Page
I'm a Professor in the Physics and Astronomy
Department at Dartmouth. In the Fall term, I will be teaching
Astronomy 2/3. The course web sites can be accessed via
My research is in the general area of stellar evolution and stellar
populations. I'm particulary interested in the ages of globular clusters (see a picture of their locations) and the formation of the Milky Way. Below is
a brief summary of some of my current research projects.
SIM-'Lite' is a NASA telescope designed to obtain very accurate positions
of stars. With this data, astronomers can search for Earth-like planets
around near-by stars and determine the distances to stars in the Milky Way.
SIM-'Lite' would be launched into an Earth-trailing orbit, and conduct
observations for a minimum of 5 years.
I am a member of the SIM-'Lite' science team, selected in 2001 to
to determine the distances and ages of the oldest stars in
is currently under study by NASA. Further details on the observations
that I would like to do on this telescope are
given here .
Much of my work involves the use of computer programs to model the
structure and evolution of stars. Modeling the evolution of stars requires
knowledge of a wide range of physical phenomena, including nuclear and atomic
physics and fluid mechanics. A
of how a stellar model is constructed highlights the important steps required
to make a stellar model. My former graduate student Aaron Dotter and myself
have calculated a large gride of
stellar evolution models and isochrones
which are available for public use.
The computer program I use to model the evolution of stars is not publicaly
available, but it can be run using a simple
web interface. This web interface
is a work in progress, and if you encounter any difficulties, please e-mail me.
The bulk of the web interface was designed by
from Research Computing at Dartmouth.
Globular Clusters and Stellar Ages
I am involved in a variety of projects to study the ages of the oldest stars
in the Milky Way. I am the principle investigator of a Hubble Space Telescope
(HST) large program to determine parallaxs to some nearby metal-poor stars. We
have been allocated 108 orbits of HST time (equivalent to 7 days) to
determine the distance to 9 nearby stars.
We will use this data to calibrate the luminsoity of metal-poor stars which
will allow us to obtain accurate distances to metal-poor globular
cluster stars with the ultimate goal of determining their ages.
I am a co-investigator of the Hubble Space Telescope
Advanced Camera for Surveys Tresury Project on
Galactic Globular Clusters. This project has obtained high quality
images of 65 galactic globula clusters.
One of the higlights of this work was a study of the globular cluster M54,
which is located in the center of the Sagittarius dwarf galaxy. The major
results of this work are illusrated in the figure below.
My CV in PDF.
Many of my papers are available from the astro-ph pre-print server
See the LANL preprint server for
my papers over the last 8 years.
Most of my publications are available via ADS
My favorite Links