Stellar Populations

Cataloging High Proper Motion Stars

High Proper Motion Star
A 4-epoch montage on the fastest high proper motion star discovered in the Lepine-Shara Proper Motion Survey, PM I13420-3415, which moves 2.55 arcseconds per year.

Museum postdoctoral fellow Sebastien Lepine and Curator Michael Shara continue cataloguing the closest one million stars to the Sun. Some of the oldest, faintest, and most metal-poor stars known have already been detected. Working with Museum graduate student Akimi Fujita, Curator Mac Low has also investigated how the ionizing radiation and supernova explosions from the first galaxies in the universe escape into the surrounding intergalactic medium, perhaps preventing the formation of nearby galaxies.

Studying Novae

Dr. Shara also detected several dozen erupting novae in the giant elliptical galaxy M87 in the Virgo galaxy cluster. The presence of extremely luminous novae in this ancient galaxy is quite unexpected, and he and AMNH Hubble postdoctoral fellow Jarrod Hurley are carrying out extensive stellar population simulations to determine the progenitors of these novae.

Wolf-Rayet Stars

Shara and colleagues have carried out a narrowband imaging survey of much of the Milky Way Galaxy, to locate the expected 5,000 pre-supernova Wolf Rayet stars scattered across our Galaxy. Spectroscopic confirmation of thousands of candidates is underway.