The symbiotic star CH Cygni

Contini, M.; Angeloni, R.; Rafanelli, P.

doi:10.1051/0004-6361/20079283

Cited by 10 publications

(21 citation statements)

References 21 publications

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“…the effect of intrinsic flux variability on our modelling method, that we present at the end of this section. Comparing the sample introduced in Table 1 with the original one studied in Paper I, we notice that CH Cyg has been removed because we have dedicated to it two detailed papers (Contini et al 2009a,c). Moreover, a new object has been added: SS73 38.…”

Section: The Samplementioning

confidence: 99%

“…The observations in the different wavelength ranges provided sufficiently reliable data. Therefore, not only the red giant star but also, sometimes, the WD could be recognized throughout the SED; however today the plural nature of the emitting nebulae and of the dust shells within the SS systems is well established (Contini 1997; Contini & Formiggini 2001, 2003; Angeloni et al 2007a, hereafter Paper I; Angeloni et al 2007b,c, and references therein; Contini, Angeloni & Rafanelli 2009a; Contini et al 2009b; Contini et al 2009c, and references therein).…”

Section: Introductionmentioning

confidence: 99%

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The spectral energy distribution of D-type symbiotic stars: the role of dust shells

Angeloni¹,

Contini²,

Ciroi³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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We have collected continuum data of a sample of D‐type symbiotic stars. By modelling their spectral energy distribution in a colliding‐wind theoretical scenario we have found characteristics common to all the systems: (1) at least two dust shells are clearly present, one at ∼1000 K and the other at ∼400 K; they dominate the emission in the infrared; (2) the radio data are explained by thermal self‐absorbed emission from the reverse shock between the stars; while (3) the data in the long wavelength tail come from the expanding shock outwards the system; (4) in some symbiotic stars, the contribution from the white dwarf in the UV is directly seen. Finally, (5) for some objects soft X‐ray emitted by bremsstrahlung downstream of the reverse shock between the stars is predicted. The results thus confirm the validity of the colliding‐wind model and the important role of the shocks. The comparison of the fluxes calculated at the nebula with those observed at the Earth reveals the distribution throughout the system of the different components, in particular the nebulae and the dust shells. The correlation of shell radii with the orbital period shows that larger radii are found at larger periods. Moreover, the temperatures of the dust shells regarding the sample are found at ∼1000 and ≤400 K, while in the case of late giants they spread more uniformly throughout the same range.

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Section: The Samplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The spectral energy distribution of D-type symbiotic stars: the role of dust shells

Angeloni¹,

Contini²,

Ciroi³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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“…To further constrain this model, we note that such velocities are characteristic of the expanding shock. We adopt therefore pre‐shock densities of ∼10 5 cm −3 as, for example, for CH Cyg (Contini et al 2009a).…”

Section: The 1962 Spectrummentioning

confidence: 99%

“…According to our recent interpretation concerning the appearance of a broad Lyα in the CH Cyg spectra at the end of the active phase 1977–1986 (Contini et al 2009a), we would like to explain the broad Hα line in BI Cru by means of the theory of charge transfer reactions between ambient hydrogen atoms and post‐shock protons at a strong shock front (Heng & Sunyaev 2008). Particularly, recall that in the circumstellar side of the WD opposite to the red giant, the effect of symbiosis is less enhanced.…”

Section: The Broad Hα Linementioning

confidence: 99%

“…On the basis that no burst has been recorded in the last 60 yr of observations, we adopt t ∼ 60 yr as a lower limit. Following the method indicated by Contini et al (2009a) for CH Cyg, a present blast wave velocity V BW = 1500–2 000 km s −1 , at least 60 yr after the outburst, would then translate to V o ∼ 5800–7700 km s −1 1 yr after the burst. A velocity of ∼5800 km s −1 is about the maximum predicted by the models of Yaron et al (2005) for nova outbursts.…”

Section: The Broad Hα Linementioning

confidence: 99%

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Shock fronts in the symbiotic system BI Crucis

Contini

Angeloni

Rafanelli

2009

Monthly Notices of the Royal Astronomical Society

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We investigate the symbiotic star BI Crucis (BI Cru) through a comprehensive and self-consistent analysis of the spectra emitted in three different epochs: 1960s, 1970s and late 1980s. In particular, we would like to find out the physical conditions in the shocked nebula and in the dust shells, as well as their location within the symbiotic system, by exploiting both photometric and spectroscopic data from radio to UV. We suggest a model which, on the basis of optical imaging, emission-line ratios and spectral energy distribution profile, is able to account for collision of the winds, formation of lobes and jets by accretion onto the white dwarf (WD), as well as for the interaction of the blast wave from a past, unrecorded outburst with the interstellar medium (ISM). We have found that the spectra observed throughout the years show the marks of the different processes at work within BI Cru, perhaps signatures of a post-outburst evolution. We then call for new infrared and millimeter observations, potentially able to resolve the inner structure of the symbiotic nebula

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The symbiotic system CH Cygni: An analysis of the shocked nebulae at different epochs

Contini¹,

Angeloni

Rafanelli

2009

Astron Nachr

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Context. We analyse the line and continuum spectra of the symbiotic system CH Cygni. Aims. To show that the colliding-wind model is valid to explain this symbiotic star at different phases. Methods. Peculiar observed features such as flickering, radio variation, X-ray emission, as well as the distribution of the nebulae and shells throughout the system are investigated by modelling the spectra at different epochs. The models account consistently for shock and photoionization and are constrained by absolute fluxes. Results. We find that the reverse shock between the stars leads to the broad lines observed during the active phases, as well as to radio and hard X-ray emission, while the expanding shock is invoked to explain the data during the transition phases.

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The symbiotic star CH Cygni

Cited by 10 publications

References 21 publications

The spectral energy distribution of D-type symbiotic stars: the role of dust shells

The spectral energy distribution of D-type symbiotic stars: the role of dust shells

Shock fronts in the symbiotic system BI Crucis

The symbiotic system CH Cygni: An analysis of the shocked nebulae at different epochs

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