Ordinary Meeting

Speaker: Professor Mark Krumholz, Research School of Astronomy & Astrophysics, ANU

Title: Formation of stars and galaxies/physics of the interstellar medium

Abstract: We’ve all learned that space is an empty vacuum, but it’s not. The space between the stars in our Galaxy contains, on average, about 1 atom per cubic centimeter. That’s a better vacuum than the best vacuum chamber we know how to make, but there are a lot of cubic centimeters in interstellar space, so the mass of all the gas between the stars adds up to about 10% of the mass of all the stars put together. The temperature of this gas varies enormously from place to place in the Galaxy, with temperatures as high as millions of degrees and as low as a few degrees above absolute zero. In the coldest regions of interstellar space, over millions of years gravity is able to draw the atoms together into immense clouds that ultimately condense into clusters of new stars. In our Galaxy, this process produces stars at a rate of about 1 new Sun per year, and the stars it makes are typically the size of the Sun or a little smaller. While we understand how this happens in general outline, many fundamental questions remain unanswered. What sets the rate at which stars form? What determines the final sizes of the individual stars? Where did our Sun form, and what happened to its siblings, the stars that formed out of the same cloud?

Biography: Mark Krumholz is a theoretical and computational astrophysicist whose research focuses on flows of interstellar gas, the formation of stars and galaxies, and numerical and statistical methods for astrophysical simulation and data analysis. He received his PhD in 2005 from the University of California, Berkeley, was a Hubble Postdoctoral Fellow at Princeton University from 2005 - 2008, and was on the faculty of the University of California, Santa Cruz from 2008 - 2015. He has been a professor at the ANU since 2015.