Are either X Her or g Her Binary Stars?
Abstract
X Her (HD 144205) and g Her (HD 148783) were observed by Shawl (AJ, 80, 602, 1975) to exhibit polarization position angles that varied with time in peculiar ways. For example, for X Her, the variations in the B- and I-filters were significant and uncorrelated, while for g Her a possible periodic position angle variation was found. At the time of that work, a literature search found no papers indicating that either star was binary, which conceivably could explain the observed variations. For this reason, in spring 2001 these stars were placed on the observing list of the second author to obtain high precision radial velocities (2001-2003 using the DAO radial velocity scanner, while from 2004 onward using a CCD). The velocity errors are estimated to be les than 1 km/s. Nearly 100 observations were collected over a range of 2343 days.
After we began collecting data, Hinkle et al. (AJ 123, 1002, 2002) published a paper that included radial velocity observations of both our program stars. For both stars they had 25 spectra during 1849 days between 1995 and 2000. X Her showed obvious velocity variations with a 666 day period. Lebzelter (Astron. Astrophys 351, 644, 1999) obtained a finer grid of data and found some complex short-period variations. For g Her, they found an 838 day period, which is consistent with the long-period variation in the V-band. We will present the interim results of our analysis of the more recent data. * Guest observer at the Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada.- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AAS...211.6008S