Gemini South Head of Science Operations | Operations
I spend most of my professional life herding 23 extremely talented cats
through the corral of Gemini South Science Operations. However, I am also very interested in star and planet formation, and specifically intermediate mass stars, known as Herbig Ae/Be stars. One particularly interesting subset of these are the highly variable UXOR stars (named after UX Ori). These stars are thought to be viewed nearly edge-on through highly inhomogeneous-- or clumpy or puffed or warped-- circumstellar disks. At times, the material in the disks obscure up to 90% of the starlight (at minimum these stars dim by 1-3 magnitudes in the optical), while at other times the starlight is relatively unobscured.
Recently, I have been more interested in counting and characterizing physical companions to Herbig Ae/Be stars. We started out taking spectra of companion stars to see what types of stars they were, but soon found that relatively few are known, mainly for lack of looking. So we have embarked on a major survey to discover and catalog potential companions to these young stars. We are doing this primarily with the near-infrared imager (NIRI) and AO system (Altair) at Gemini North. We've been at this for a couple of years and have now more than doubled the number of known Herbig Ae/Be stars with likely companions. The multiplicity fraction in this class of stars was thought to be high based on smaller samples and our larger sample bears this out. We have also collected quite a number of near-infrared spectra of the companion stars and find an interesting variety of spectral characteristics. My collaborators in this are Nicole van der Bliek at CTIO across the street in La Serena, Chile, Sandrine Thomas at UC Lick Observatory in California, and Greg Doppmann at CTIO in Tucson, Arizona.
In my current position at the Observatory, I support the people that support the Gemini users at Gemini South. These are the staff astronomers and scientists, Gemini Science Fellows, System Support Associates and Data Analyst Specialists at Gemini South. They make my job easy by doing their jobs so well! And we all get to live in La Serena, Chile to boot. You can learn more about Gemini Science Operations from our web pages.
While our major publications regarding Herbig Ae/Be multiplicity are still in preparation, our project has leant itself to student involvement and you can find several AAS posters reporting on various aspects.
In 2008, I was fortunate to attend a small conference on the nature of UX Ori stars at the Crimean Astrophysical Observatory in Yalta, Ukraine, led by Dr. Vladimir Grinin.
My ADS publication list is here.