Physics
Scientific paper
Jan 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995phdt.........6f&link_type=abstract
Thesis (PH.D.)--UNIVERSITY OF CALIFORNIA, LOS ANGELES, 1995.Source: Dissertation Abstracts International, Volume: 56-11, Sectio
Physics
34
Star Formation
Scientific paper
The purpose of this dissertation is to find and characterize the hot, young emission-line stars within 50 parsecs of the Galactic Center. These stars are thought to be less than 10^7 years old, and they represent the most easily identifiable components of recent star formation. Inspired by the recent discovery of emission-line stars within the central parsec, this study constitutes the first wide-area search for such stars. New near-infrared techniques were developed and used to discover and characterize emission-line stars in the survey region. The efforts in this project formed the basis for commissioning the spectroscopic mode of the new UCLA double-beam infrared camera. Several new emission-line stars were found, and they support the conclusion that star formation over the time period of ~0.2 to 1 times 10^7 years has been limited to regions near thermal radio emission in the survey range. The types of stars in each star formation region suggest considerable variation in birth times, such that stars in the younger sites are still enshrouded by dust and have not yet evolved into the Wolf-Rayet phase. Measured velocities for the emission-line stars and HII regions are consistent with a physical connection between the hot stars and radio continuum features. The variations in extinction over the survey region support earlier suggestions that the obscuring molecular clouds along the line of sight are actually at the distance of the Galactic Center. Two molecular clouds revealed in the extinction data are thought to be star-formation sites, but no emission-line stars were found at or near them. Two new emission-line stars have been found in the inner parsec where approximately two dozen similar stars are known to exist. These stars are thought to be in a transitional evolutionary phase between the main sequence and the Wolf-Rayet stage. Their existence provides important clues about recent star formation in the Galactic Center, but a rigorous explanation for their origin, stellar mergers versus starburst, still awaits an assay of the OB-star population or an accurate determination of the number of carbon versus nitrogen Wolf-Rayet stars.
No associations
LandOfFree
A Search for Emission-Line Stars Near the Galactic Center does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Search for Emission-Line Stars Near the Galactic Center, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Search for Emission-Line Stars Near the Galactic Center will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-837165