Karlheinz Wolf
Vereinigung der Sternfreunde, Fachgruppe Spektroskopie, Germany
Doppler tomography of Algol
Abstract:
Algol (Beta Persei) represents a hierarchical triple system with the inner pair being a semi-detached, eclipsing binary with mass transfer from the Roche lobe filling subgiant Algol B (the secondary) to the main sequence star Algol A (the primary).
Our group of amateur astronomers in Germany and Austria has recorded numerous spectra of the system, predominatly around Halpha, between the years 2014 and 2026.
To characterize the mass transfer, we performed Doppler tomography with the associated difference spectra, obtained by subtracting phase dependant, synthetic spectra of the system from the measured spectra. We largely confirmed results documented in the literature. Main features are the gas stream originating from the inner Lagrange point L1 with a possible contribution of chromospheric activity of the secondary and the blocking of the gas stream on his way to and the annulus around the primary. Virtually no signatures were found from a hot spot and from an entire accretion disk around the primary.