I am currently an Associate Adjunct Professor in the Astronomy Department at the University of California, Berkeley.

My expertise is in providing direct images of planetary systems around nearby stars. I use some of the world's most advanced observatories, such as the Hubble Space Telescope, Keck Observatory, and the Gemini Telescopes. One of my most well-known images is the planetary system surrounding Fomalhaut (see below), which is a bright star located 25 light years away in the constellation Pisces Australis. Though direct images are difficult to obtain and currently quite rare, they provide unique and fundamental information about exoplanetary systems, such as:

  • The masses of exoplanets, by analyzing how bright they appear and how stable their orbits should be assuming different properties.
  • Their composition, by analyzing the color of thermal emission from the planet, or by obtaining a spectrum.
  • The origin of exoplanets, by comparing their current observed properties with simulations of how planets form in a circumstellar disk and subsequently evolve.

Ultimately, these data will give us an empirical notion of how common or rare our own planetary system must be in our own galaxy and throughout the universe.

Here is a one page handout to help viewers see the May 20, 2012, annular solar eclipse from Northern California: pdf -- jpg

For images concerning Fomalhaut b, the recent visible light detection of an exoplanet candidate in orbit around the bright star Fomalhaut, please see the NASA/STScI website:

As of April, 2012, there have been three independent efforts (including myself) where the HST observations were downloaded from the HST data archive, Fomalhaut b was detected, and orbital motion is found. The suggestion that it is a spurious noise artifact is entirely against the consensus view. The next Hubble observations are scheduled for the end of May, 2012, using the STIS coronagraph.

We should be commissioning the Gemini Planet Imager in late 2012. GPI is an advanced adaptive optics system and coronagraph designed to directly detect warm planets and debris belts surrounding young stars such as Fomalhaut. We expect that by 2014 various GPI science projects will discover and characterize 10x more exoplanets via direct imaging and spectroscopy than existed in 2011. Please see the GPI website for more info. This project has been ten years in the making, and I currently serve on the GPI Science Steering Committee and the Debris Disk Science Team.

Every year I look forward to hearing from the undergraduates all over the world applying for astronomy graduate school at Berkeley. The breadth of topics available for astrophysics doctoral work here in Berkeley is truly incredible. The most common question I receive is "Hi, I'm applying for grad school, can I come work with you?" The answer is that our admissions process does not depend on available graduate student research slots with various faculty. Instead, we offer admission to the best students in our pool of applicants. Once they arrive as graduate students, they will naturally find a research topic that they are interested in with one of our distinguished faculty. The astronomy department web page has a wealth of information about our program. Prospective students may also be interested in looking at the wiki maintained by the current astronomy graduate students.

Spirit of Lyot confernce logo

In 2007 I founded the Spirit of Lyot conference. The fundamental motivation is to nurture a balance between scientific talent and experimental innovation that is personified by the career of the famous French astronomer Bernard Lyot, inventor of the solar coronagraph.

In 2010 our colleagues in France hosted the second Spirit of Lyot conference in Paris, with a 50 percent increase in attendance.

In 2012 we will announce the third Lyot conference, probably to take place in 2013.