Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2009-02-03
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
accepted by AJ
Scientific paper
10.1088/0004-6256/137/4/3800
Cool subdwarfs of types K and M are the fainter counterparts of cool main sequence dwarfs that dominate the Galactic population. In this paper we present the results of an optical speckle survey of 62 confirmed cool subdwarf systems within 60 pc. We have resolved two new companions and confirmed two previously known companions with separations 0\farcs13 to 3\farcs29. After including previously known wide companions and all known spectroscopic binaries, we determine the multiplicity rate of cool subdwarfs to be 26$\pm$6%, which is somewhat lower than comparable main sequence stars, which have a multiplicity rate of 37$\pm$5%. We find that only 3% of the cool subdwarfs surveyed have companions within 10 AU, 3% have companions between 10 and 100 AU, and 14% have companions beyond 100 AU. The other 6% of cool subdwarfs are spectroscopic binaries. This is very different from K/M dwarfs that have most companions (13%) at separations closer than 10 AU. However, because a search for close binaries among a large sample of nearby cool subdwarfs remains elusive, it is not yet settled whether or not the multiplicity rates are significantly different. Nonetheless, several different observational results and theories pointing to a possible dearth of subdwarf multiples are discussed.
Hartkopf William I.
Henry Todd J.
Jao Wei Chun
Mason Brian D.
Ramos Stephanie N.
No associations
LandOfFree
Cool Subdwarf Investigations II: Multiplicity 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 Cool Subdwarf Investigations II: Multiplicity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cool Subdwarf Investigations II: Multiplicity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-298043