Past Colloquia
Dreams of Streams: Exploring the stellar outskirts of nearby galaxies
Cody Hall
Daniel Dale (University Wyoming)
April 08, 2016
14:00 - 15:00
I will review highlights from the Spitzer Extended Disk Galaxy Exploration Science (EDGES) survey, a Warm Mission program to obtain sensitive infrared imaging for 92 nearby galaxies. Highlights will include the radial trends in their star formation histories as well as characterizations of their outermost…
Rogue Waves on Pulsating White Dwarf Stars
Cody Hall
JJ Hermes (U. of North Carolina)
April 01, 2016
14:00 - 15:00
While it has been an efficient planet-discovery machine, the unblinking photometry of the Kepler space telescope has also revolutionized the way we look at pulsating stars. I will discuss some of the rapid advances Kepler has enabled in our understanding of white dwarf stars, including…
Extrasolar Storms: Cloud Physics and Atmospheric Dynamics in Brown Dwarfs and Exoplanets
Cody Hall
Daniel Apai (University of Arizon)
March 18, 2016
14:00 - 15:00
Observations of directly imaged and transiting exoplanets and brown dwarfs reveal the wide-spread presence of condensate clouds. These clouds profoundly influence the energy transport through ultracool atmospheres and impact their pressure-temperature profiles. Yet, the structure and properties of these cloud layers remain mostly unknown and…
Direct imaging of extrasolar planets and the Gemini Planet Imager
Cody Hall
Bruce Macintosh (Stanford)
March 11, 2016
14:00 - 15:00
Abstract: While thousands of extrasolar planets and candidates have now been detected, but almost all through indirect methods such as transit photometry or radial velocity. Though statistically powerful, these techniques provide in most cases just a basic measurement of an object’s size and orbital parameters,…
Convection in Cool Stars, as Revealed through Stellar Brightness Variations
Cody Hall
Fabienne Bastien (Penn State)
March 04, 2016
14:00 - 15:00
Abstract: As a result of the high precision and cadence of surveys like MOST, CoRoT, and Kepler, we may now directly observe the very low-level light variations arising from stellar granulation in cool stars. Here, we discuss how this enables us to more accurately determine…
Ilse Cleeves (Harvard)
Cody Hall
Ilse Cleeves (Harvard)
February 26, 2016
14:00 - 15:00
details to follow
Clustering Redshifts: A New Era of Distance Measurement
Cody Hall
Mubdi Rahman, John Hopkins University
February 19, 2016
14:00 - 15:00
Measuring the true distance of objects seen on the celestial sphere is a challenge that has plagued astronomy from its earliest days. The classical solution to this problem for extragalactic systems has been measuring the regression velocity through spectroscopy to determine a redshift-related distance. However…
Toward a Holistic View of Star Formation
Cody Hall
Rob Gutermuth (UMASS Amherst)
February 12, 2016
14:00 - 15:00
Abstract: Our general picture of the process of forming stars from molecular clouds has held together quite well for the past few decades, but a detailed, predictive theory of star formation remains frustratingly out of reach. What determines the clustering of newborn stars? What sets…
An Astronomical Time Machine: Light Echoes from Historic Supernovae and Eruptions
Cody Hall
Armin Rest (Space Telescope Science Institute)
February 05, 2016
14:00 - 15:00
Tycho Brahe’s observations of a supernova (SN) in 1572 challenged the teachings of Aristotle that the celestial realm was unchanging. We have discovered a way to see the same light that Tycho saw 440 years ago by observing SN light that only now reaches Earth…
Stellar Magnetic Fields and Stellar Evolution
Cody Hall
Gregg Wade (RMC/Queens University)
January 29, 2016
14:00 - 15:00
All stars are natural magnets, thanks to the dynamic, electrically conductive gases that compose them. And because the magnetic fields of stars can be very strong, they represent a basic physical ingredient in the theory of stellar structure and evolution. In recently years it has…