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Tomov, N. A.; Tomova, M. T.

doi:10.1023/a:1013126728911

Cited by 21 publications

(49 citation statements)

References 8 publications

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“…In addition we calculate the emission measure of its circumbinary nebula using U photometric data from the literature. We continue our search, initiated in a previous work (Tomova & Tomov 1999), for observational evidence to support any single outburst model. On one hand the frequency of appearance of a stellar wind from the hot component of the system and its mass-loss rate obtained by us cannot be explained in the framework of the thermonuclear model.…”

Section: In 1994 It Entered In a Newmentioning

confidence: 87%

“…In this way AG Dra underwent five optical brightenings, the last of them being in 1998. Analysis of the photometric data (Montagni et al 1996;Greiner et al 1997;Skopal 1998;Petrik et al 1998;Tomova & Tomov 1998; showed that the growth of the visual light is due to the increased radiation of the circumbinary nebula. Different models about the outburst activity of AG Dra have been proposed.…”

Section: In 1994 It Entered In a Newmentioning

confidence: 99%

“…We calculated the 6563Å/5500Å flux ratio of α Boo and scaled it to the dereddened visual flux of AG Dra taken in its quiescent orbital minimum, when the nebular emission can be supposed to be negligible. Both groups of variations of the optical continuum of AG Dra, the quiescent and the active ones, are caused by the nebular emission (Montagni et al 1996;Greiner et al 1997;Tomova & Tomov 1998;. That is why the contribution of the circumbinary nebula at the wavelength position λ 6563Å must be found at each epoch of Hα observation.…”

Section: Observation and Reductionmentioning

confidence: 99%

“…In this way we obtained the continuum flux of the AG Dra system at this wavelength. For calculation of all line fluxes the photometric data of Skopal (1998), Petrik et al (1998) and Tomova & Tomov (1998) were used.…”

Section: Observation and Reductionmentioning

confidence: 99%

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Hydrogen and helium emission of the symbiotic binary AG Draconis during an active phase (1996–1997)

Tomov

Tomova

2002

A&A

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Abstract. High resolutions observations of the regions of the Hα and He ii 4868 lines of the symbiotic star AG Dra were performed during its time of activity in 1996-1997. Profiles, fluxes and radial velocity data of these lines as well as the line He i 4713 were obtained. The Hα fluxes changed in correlation with the optical light. The emission measure of the circumbinary nebula of the system at several epochs during its 1994-1998 active phase was also calculated using Balmer continuum emission on the basis of U photometric data from the literature. It was increased by factors up to 36 above its quiescent maximal value. After the 1996 and 1997 light maxima the profile of the He ii 4868 line contained a broad emission component indicating mainly a stellar wind from the hot secondary with a velocity of 1100 ÷ 1300 km s −1 . The mass-loss rate of this star was estimated to be about 1 ÷ 2 10 −7 (d/1.7 kpc) 3/2 M yr −1 . The growth of its Lyman luminosity however is not sufficient to explain the increased nebular emission during the active phase. A view that this emission could be the result of both a rise of the mass-loss rate of the cool giant of the system and a rise of the Lyman flux of the hot luminous secondary, being in a steady-state burning regime during the quiescence, is discussed.

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Section: In 1994 It Entered In a Newmentioning

confidence: 87%

Section: In 1994 It Entered In a Newmentioning

confidence: 99%

Section: Observation and Reductionmentioning

confidence: 99%

Section: Observation and Reductionmentioning

confidence: 99%

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Hydrogen and helium emission of the symbiotic binary AG Draconis during an active phase (1996–1997)

Tomov

Tomova

2002

A&A

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“…The position of the U band is close to the Balmer limit. The symbiotic systems with strong hydrogen emission spectrum (AG Peg, AG Dra) have an apparent continuum which on the long wavelength-side of the Balmer limit has the same flux as on the short wavelength-side (see for example Tomov et al 1998;Tomova & Tomov 1999) because of the blending of the Balmer lines with high numbers. We supposed, that the Z And system has the same characteristics since its Balmer lines are strong and are seen in emission up to H 32 (Boyarchuk 1967a) and took the value of the hydrogen coefficient on the short wavelength-side (Osterbrock 1974).…”

Section: The Quiescent Phasementioning

confidence: 99%

Mass ejection by the symbiotic binary Z And during its 2000–2002 outburst

Tomov

Taranova²,

Tomova

2003

A&A

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Abstract. Broad-band UBV JHKLM data have been obtained at the time of the quiescent orbital photometric maximum of the classical symbiotic binary system Z And and at some epochs of its 2000-2002 active phase. The data of the active phase are related to the time of the optical maximum and after it when the star was returning to quiescence. Broad-band quiescent RI photometry from the literature was also used to obtain the parameters of the cool component of this binary. All of these data suggest that the hot compact component has undergone a major expansion and the emission measure of the circumbinary nebula has also increased. Some mechanisms for interpretation of the outburst are reviewed.

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Interacting Winds in Eclipsing Symbiotic Systems – The Case Study of EG Andromedae

Calabrò

2014

J Astrophys Astron

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Cited by 21 publications

References 8 publications

Hydrogen and helium emission of the symbiotic binary AG Draconis during an active phase (1996–1997)

Hydrogen and helium emission of the symbiotic binary AG Draconis during an active phase (1996–1997)

Mass ejection by the symbiotic binary Z And during its 2000–2002 outburst

Interacting Winds in Eclipsing Symbiotic Systems – The Case Study of EG Andromedae

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