IP Pegasi: Investigation of the accretion disk structure. Searching evidences for spiral shocks in the quiescent accretion disk

• Main Authors: Neustroev, V. V, Borisov, N. V, Barwig, H, Bobinger, A, Mantel, K. H, Simic, D, Wolf, S
• Format: Journal Article
• Language: English
• Published: 19-07-2002
• Subjects: Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.astro-ph/0207418

Astron.Astrophys. 393 (2002) 239-250 We present the results of spectral investigations of the cataclysmic variable
IP Peg in quiescence. Optical spectra obtained on the 6-m telescope at the
Special Astrophysical Observatory (Russia), and on the 3.5-m telescope at the
German-Spanish Astronomical Center (Calar Alto, Spain), have been analysed by
means of Doppler tomography and Phase Modelling Technique. From this analysis
we conclude that the quiescent accretion disk of IP Peg has a complex
structure. There are also explicit indications of spiral shocks. The Doppler
maps and the variations of the peak separation of the emission lines confirm
this interpretation. We have detected that all the emission lines show a rather
considerable asymmetry of their wings varying with time. The wing asymmetry
shows quasi-periodic modulations with a period much shorter than the orbital
one. This indicates the presence of an emission source in the binary rotating
asynchronously with the binary system. We also have found that the brightness
of the bright spot changes considerably during one orbital period. The spot
becomes brightest at an inferior conjunction, whereas it is almost invisible
when it is located on the distant half of the accretion disk. Probably, this
phenomenon is due to an anisotropic radiation of the bright spot and an eclipse
of the bright spot by the outer edge of the accretion disk.