CH Cygni II: Optical Flickering from an Unstable Disk

Details CH Cygni II: Optical Flickering from an Unstable Disk CH Cygni II: Optical Flickering from an Unstable Disk

2002-11-04

arxiv.org/abs/astro-ph/0211041v1

Astrophys.J. 584 (2003) 1027-1034

Astronomy and Astrophysics

Astrophysics

8 pages, 5 figures, to appear in the ApJ

Scientific paper

10.1086/345902

CH Cygni began producing rapid, stochastic optical variations with the onset of symbiotic activity in 1963. We use changes in this flickering between 1997 and 2000 to diagnose the state of the accretion disk during this time. In the 1998 high state, the luminosity of the B-band flickering component was typically more than 20 times higher than in the 1997 and 2000 low states. Therefore, the physical process or region that produces the flickering was also primarily responsible for the large optical flux increase in the 1998 high state. Assuming that the rapid, stochastic optical variations in CH Cygni come from the accretion disk, as in cataclysmic variable stars, a change in the accretion rate through the disk led to the 1998 bright state. All flickering disappeared in 1999, when the accreting WD was eclipsed by the red giant orbiting with a period of approximately 14 yr, according to the ephemeris of Hinkle et al. and the interpretation of Eyres et al. We did not find any evidence for periodic or quasi-periodic oscillations in the optical emission from CH Cygni in either the high or low state, and we discuss the implications for magnetic propeller models of this system. As one alternative to propeller models, we propose that the activity in CH Cygni is driven by accretion through a disk with a thermal-viscous instability, similar to the instabilities believed to exist in dwarf novae and suggested for FU Ori pre-main-sequence stars and soft X-ray transients.

Affiliated with

Also associated with

No associations

Rating

CH Cygni II: Optical Flickering from an Unstable Disk 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 CH Cygni II: Optical Flickering from an Unstable Disk, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and CH Cygni II: Optical Flickering from an Unstable Disk will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-73346