Alex Gianninas

Visiting Assistant Professor of Astronomy, Amherst College
Photo of Alex Gianninas in front of star wheel


Ph.D. (Physics/Astrophysics), Université de Montréal (2011)
M.Sc. (Physics/Astrophysics), Université de Montréal (2005)
B. Sc. (Honors Physics), McGill University (2003)


University of Massachusetts Department of Astronomy LGRT-B 619E 710 North Pleasant Street Amherst, MA 01003-9305



Research Interests: 

White dwarfs (WDs) are the dense burned-out cores of all stars with initial masses less than roughly eight times the mass of the sun (i.e. M < 8 M⊙). This represents more than 97% of all stars in the Milky Way. Normal WDs have masses of M ~ 0.6 M⊙ packed into a volume about the size of the Earth. Since there are no longer any nuclear reactions powering the star, it simply cools as a function of time over the course of billions of years.
My research involves the observation and study of WDs. For the most part, I conduct ground-based optical observations in order to study the different properties of WDs and obtain measurements of their fundamental parameters such as their surface temperature, gravity, and chemical composition. I'm also interested in pulsating WDs, WDs in various types of binary systems and WDs that harbor circumstellar debris disks.

As a postdoctoral researcher, I worked extensively on the discovery and analysis of extremely low mass (ELM) WDs. Contrary to their more massive brethren, these WDs are necessarily the product of the evolution of compact binary systems since the Universe is not yet old enough for ELM WDs to have been produced through normal single-star evolution. In fact, virtually all ELM WDs are found in short-period (P < 1 day) binary systems. This is a relatively new area of research and we are discovering many of the same phenomena seen in normal WDs but in an essentially unexplored mass regime. We have also observed several new phenomena that could only arise in such close binary systems. As such, the study of ELM WDs is really exciting as we try to understand the origin and evolution of a whole new population of WDs.

Teaching Statement: 

Over the last several years I have taught introductory astronomy courses for non-majors as well as introductory-level geology and earth science courses and college physics (algebra-based) with the associated labs. In addition, I have taught several space studies courses in an online setting. I enjoy exposing non-science majors to the scientific method and the wonders of astronomy and the night sky as well as debunking commonly held myths and misconceptions about science, physics, and astronomy.