Friday, December 2, 2011
Dr. Michael Shara, Curator in the Department of Astrophysics at the American Museum of Natural History, will address the AAA Friday, December 2, on òÀÜHow Novae and Supernovae Are Connected.òÀÝ The free public lecture begins at 6:15 p.m. in the Kaufmann Theater of the AMNH.
Discussing what heòÀÙll talk about and why itòÀÙs significant, Shara tells us:
òÀÜThe Nobel physics prize of 2011 was awarded to three astrophysicists credited with discovering òÀØdark energy,òÀÙ the mysterious entity which accounts for 70 percentˆàof all the mass-energy in the universe, and which is causing the universeòÀÙs expansion to accelerate. Measuring and understanding dark energy hinges on understanding type Ia supernovae, the òÀØstandard candlesòÀÙ used by the Nobel prize winners. Are these luminous objects really all the same luminosity, or do they have subtle differences whose misinterpretation could mimic an acceleration of the universe?
òÀÜThe only way to understand type Ia supernovae is to know, with certainty, exactly what kind of star gives rise to them. This would allow astronomers to determine if these kinds of stars change systematically over 13 billion years, and thus if we might be misinterpreting them as standard candles when they are, in fact, not standard at all.
òÀÜSix models for type IaòÀÓsupernova progenitors, the stars that give rise to them, have been proposed in the past 30 years, including several kinds of novae. IòÀÙll describe these models, and show how Hubble Telescope observations have made dramatic progress in the past six months in ruling out all but two of these models. IòÀÙll also answer the question, could dark energy not really be there?òÀÝ
Prior to joining the museum 12 years ago, Shara spent 17 years at the Space Telescope Science Institute (STScI) at Johns Hopkins, where he was responsible for peer-review committees for the Hubble.
SharaòÀÙs principal responsibilities at the museum are to conduct astronomical research, train young astrophysicists, and build space shows and exhibitions. He received his Ph.D. from Tel Aviv University and holds masteròÀÙs and bacheloròÀÙs degrees from the University of Toronto. Shara has been visiting and adjunct professor at Columbia University and astronomer with tenure at the STScI. He curated the AMNHòÀÙs Einstein exhibition as well as several AMNH space shows seen by millions of people worldwide. SharaòÀÙs òÀÜBeyond Planet EarthòÀÝ special exhibition opened at the AMNH November 19.
SharaòÀÙs research interests include the structure and evolution of novae and supernovae, collisions between stars and the remnant descendants of those collisions, and the populations of stars inhabiting star clusters and galaxies.