Multispectral analysis in the UV, optical and IR of HDE 245770 = A 0535+26.
Giovannelli, F.; Hensberge, H.; Persi, P.; Burger, M.; Bartolini, C.; Guarnieri, A.; Piccioni, A.; Ferrari-Toniolo, M.; Giangrande, A.; De Loore, C.; van Dessel, E. L.; Hellings, P.; van Diest, H.
Belgium, Italy
Abstract
The characteristics of the Be/X-ray binary system HDE 245770/A0535+26 are examined from UV, visual, IR and X-ray data. A sequence of observations in the optical preceding an X-ray outburst is interpreted as the ejection of a shell by the Be primary. An evolutionary scenario is presented that produces a system like HDE 245770. An effective temperature of 26000±2000K is derived for the Be star. The mass loss rate through stellar wind from the primary is determined. The Be star is not filling its Roche lobe and there is no accretion disk around the compact companion. The system configuration can be simulated with an evolution code allowing for the simultaneous evolution of two components - a 20 M_sun; primary and a 15 M_sun; secondary - producing Be/X-ray binaries of this kind, with systems like φ Per as progenitor.