A SNAPSHOT Survey of Sharp-Lined Early B-Type Stars
Abstract
Although spectrum synthesis studies of the UV spectra of sharp-lined main sequence B stars provide us with some our best determinations of the abundances of the Fe group and neutron capture elements and the chemical evolution in our galaxy and the Magellanic Clouds, the HST archive is virtually devoid of high resolution spectra of the bright nearby B stars that have become to be regarded as abundance standards. For example, there are NO observations of HR 1886, iota Her, and tau Her, the sharpest-lined representatives {V sin i < 5 km/s} of spectral classes B1 V, B3 IV-V and B5 IV, and only a few tiny spectral intervals of gamma Peg {B2 IV}. Information on the abundances of the Fe group is important for computing opacities for stellar evolution calculations and for determining astrophysical f-values. There are no suitable galactic standards in the HST database to compare with recent HST/STIS observations of B stars in the Magellanic Clouds and the likely future observations of similar objects in M31 and other nearby galaxies. To correct this deficiency, we propose SNAPSHOT observations with the STIS E140M and E230M gratings of 33 of the best bright abundance standards in nearby clusters and the galactic field. Using this data we will determine the abundances of the Fe group and heavy elements using the technique of spectrum synthesis with LTE and NLTE treatments. We waive the proprietary period.
- Publication:
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HST Proposal
- Pub Date:
- July 2003
- Bibcode:
- 2003hst..prop.9848P