The recent 1994-1995 active phase of AG Draconis has given us for the first time the opportunity to follow the full X-ray behaviour of a symbiotic star during two successive outbursts and to compare with its quiescence X-ray emission. With \ros observations we have discovered a remarkable decrease of the X-ray flux during both optical maxima, followed by a gradual recovering to the pre-outburst flux. In the UV the events were characterized by a large increase of the emission line and continuum fluxes, comparable to the behaviour of AG Dra during the 1980-81 active phase. The anticorrelation of X-ray/UV flux and optical brightness evolution is shown to very likely be due to a temperature decrease of the hot component. Such a temperature decrease could be produced by an increased mass transfer to the burning compact object, causing it to slowly expand to about twice its original size.

Greiner, J., Bickert, K., Luthardt, R., Viotti, R., Altamore, A., González Riestra, R. (1996). UV and X-Ray Monitoring of AG Draconis During the 1994/1995 Outbursts. In Supersoft X-Ray Sources (pp.267-278). Springer-Verlag [10.1007/BFb0102270].

UV and X-Ray Monitoring of AG Draconis During the 1994/1995 Outbursts

ALTAMORE, Aldo;
1996-01-01

Abstract

The recent 1994-1995 active phase of AG Draconis has given us for the first time the opportunity to follow the full X-ray behaviour of a symbiotic star during two successive outbursts and to compare with its quiescence X-ray emission. With \ros observations we have discovered a remarkable decrease of the X-ray flux during both optical maxima, followed by a gradual recovering to the pre-outburst flux. In the UV the events were characterized by a large increase of the emission line and continuum fluxes, comparable to the behaviour of AG Dra during the 1980-81 active phase. The anticorrelation of X-ray/UV flux and optical brightness evolution is shown to very likely be due to a temperature decrease of the hot component. Such a temperature decrease could be produced by an increased mass transfer to the burning compact object, causing it to slowly expand to about twice its original size.
1996
Greiner, J., Bickert, K., Luthardt, R., Viotti, R., Altamore, A., González Riestra, R. (1996). UV and X-Ray Monitoring of AG Draconis During the 1994/1995 Outbursts. In Supersoft X-Ray Sources (pp.267-278). Springer-Verlag [10.1007/BFb0102270].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/186333
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