Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010mnras.407..681m&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Volume 407, Issue 1, pp. 681-690.
Astronomy and Astrophysics
Astronomy
2
Methods: Statistical, Catalogues, Surveys, Astrometry, Proper Motions, Stars: White Dwarfs
Scientific paper
A new method for combined calculations of proper motions (PMs) based on accurate measurements of POSS1 and POSS2 epoch plates is given. The positional accuracy of various surveys and catalogues is estimated, and statistical weights for each of them are established. To achieve the best positions, weighted averaging of direct measurements on DSS1/DSS2, and data from APM, MAPS, USNO-A2.0, USNO-B1.0 and GSC 2.3.2 catalogues were used. The rms accuracy of positions achieved for POSS1 is 119 mas in each coordinate and 168 mas total, and for POSS2 it is 69 mas in each coordinate and 98 mas total. Using these accurate positions and the large separation in years between POSS1 and POSS2, we calculated the best possible PMs: 3.9 masyr-1 in each coordinate and 5.5 masyr-1 total. We developed methods to control and exclude the accidental errors that appear in any survey. We compared and combined our PMs with those given in USNO-B1.0, SDSS DR7 and Tycho-2 catalogues and obtained even better results: 3.0 masyr-1 in each coordinate and 4.2 masyr-1 total PM. This approach was applied to the First Byurakan Survey blue stellar objects, containing significant numbers of white dwarfs and subdwarfs. In total, 640 objects were revealed with PM >=10 masyr -1, the detection limit for this method, and an electronic table of these objects is given. For more confident PMs, we adopt the limit 20 masyr-1 (333 objects). Adopting a 50 km s-1 upper limit for tangential velocities, we calculated maximum distances and absolute magnitudes and estimated luminosity types for these objects, obtaining 185 probable white dwarfs (M > 8mag), 69 possible white dwarfs (6 < M < 8mag), and 42 candidate subdwarfs/white dwarfs (3 < M < 6mag). Given that we rediscovered 141 genuine white dwarfs among the classified objects, the success rate for the discovery of white dwarfs is estimated as 83 per cent, and as 38 per cent for our probable and possible white dwarfs, respectively.
Mickaelian Areg M.
Sinamyan Parandzem K.
No associations
LandOfFree
Proper motions and natures of First Byurakan Survey blue stellar objects 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 Proper motions and natures of First Byurakan Survey blue stellar objects, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Proper motions and natures of First Byurakan Survey blue stellar objects will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1504468