Doppler Tomography

0 new
0 new
0 new
0 new

Project log

J. Echevarria
added 3 research items
High-dispersion time-resolved spectroscopy of the unique magnetic cataclysmic variable AE Aqr has been obtained during four bserving runs separated by more than nine years. The high spectral resolution obtained from the AAT and SPM allows us to find the fundamental parameters of the binary. Doppler tomography of the emission lines show that during the first observations a complex and variable structure is present but nevertheless show a small disc component; the presence of this accretion disc is more than evident during other runs especially during January 2002. We also present tomographic evidence of asymmetric brightness of hot and cool spots in the secondary star. The rotational double-sined profile of AE Aqr B has been detected with great accuracy. The shape of our observed rotational velocity variations around phase 0.5 indicate that the inclination is higher that previoulsy thought. We discuss the disk versus stream models on this star and suggest a possible coupling of the magnetic fields of both the primary and secondary stars.
We have observed WZ Sge at low resolution spectroscopy during the 2001 superoutburst. During the first stage of the smooth decline and before the echo outubrsts appeared we have detected an emmision line component associated with the white dwarf. This emmision comes mainly in the form of Hydrogen and Helium I lines and its position as the orbital period is covered is consistent with the position of the white dwarf. We discuss the implications of such a discovery.
To mark the half-century anniversary of this newly-born field of Cataclysmic Variables, a special emphasis is made in this review, on the Doppler Effect as a tool in astrophysics. The Doppler Effect was in fact, discovered almost 170 years ago, and has been since, one of the most important tools which helped to develop modern astrophysics. We describe and discuss here, its use in Cataclysmic Variables which, combined with another important tool, the tomography, first devised for medical purposes 70 years ago, helped to devise the astronomical Doppler Tomography, developed only two decades ago. A discussion is made since the first trailed spectra provided a one dimensional analysis of these binaries; on the establishment of a 2D velocity profiling of the accretion discs; and unto modern techniques, which include Roche Tomography, time modulation and 3D imaging.