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| Paper: |
Resolving sdB Binary Systems with Adaptive Optics |
| Volume: |
334, 14th European Workshop on White Dwarfs |
| Page: |
435 |
| Authors: |
Ostensen, R.; Heber, U.; Maxted, P. |
| Abstract: |
A snapshot survey of spectroscopic subdwarf B plus main sequence binaries is underway, using high resolution infrared imaging with the NAOMI adaptive optics system at the William Herschel Telescope on La Palma. It is well known that a disproportionally large fraction of the field sdB stars are found in binary systems, and both interacting binary and single star evolutionary scenarios have been proposed for their origin. In the first case, all spectroscopic binaries containing sdBs need to have small separations of the order of 0.1 AU or less, in the other the binaries should have about the same distribution of separations as found for normal stars, i.e. they should be mostly in wide systems. About 100 sdB binary systems brighter than MV =14.5 are known and have spectroscopic distances between 200 pc and 1200 pc. More than 30% of them should be resolvable on short exposure J-band AO images if the non-interacting evolutionary scenario holds, none in the alternative case. Hence a snapshot survey should yield decisive constraints for the origin of sdB stars. |
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