Spectroscopy of the cataclysmic binaries CY Lyrae, TW Trianguli, and VW Vulpeculae

Citation
Jr. Thorstensen et al., Spectroscopy of the cataclysmic binaries CY Lyrae, TW Trianguli, and VW Vulpeculae, PUB AST S P, 110(754), 1998, pp. 1405-1411
Citations number
21
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
00046280 → ACNP
Volume
110
Issue
754
Year of publication
1998
Pages
1405 - 1411
Database
ISI
SICI code
0004-6280(199812)110:754<1405:SOTCBC>2.0.ZU;2-4
Abstract
From H alpha radial velocities taken in quiescence we find orbital periods of 0.1591 +/- 0.0004 days, or 3.82 hr, for CY Lyr, 0.207584 +/- 0.000007 da ys, or 4.98 hr, for TW Tri, and 0.16870 +/- 0.00007 days, or 4.05 hr, for V W Vul. The period of VW Vul is much longer than a previously published valu e, and the spectrum suggests that we caught this Z Cam star in standstill. The revision of VW Vul's period resolves its problematic status as a short- period dwarf nova that did not show superoutbursts. The quiescent spectra o f CY Lyr and TW Tri are typical of dwarf novae between outbursts, and both show the contribution of a late-type secondary, of type similar to M3.5 in CY Lyr and similar to M1 in TW Tri. From the M-dwarf contribution in the qu iescent spectrum we estimate distances of similar to 330 pc for CY Lyr and similar to 800 pc for TW Tri. On 1997 June 30 UT we observed CY Lyr in a ri se to outburst, and we present spectra obtained approximately hourly as the object brightened.