Symbiotic Novae

Mürset, U.; Nussbaumer, H.

doi:10.1007/978-94-011-0335-0_7

Cited by 65 publications

(122 citation statements)

References 12 publications

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“…It may result from the ashes of the CNO cycle that have been exposed at the star's surface as a consequence of core-envelope mixing episodes during the AGB phase of the present white dwarf. In this framework, we are then observing the nuclear processed material ejected during the recurrent outbursts that have characterized Sanduleak' star's recent history, a scenario that has been suggested also in the case of young symbiotic novae (Muerset & Nussbaumer 1995). If this idea is correct, higher-quality data should be able to highlight spatial variation in the chemical abundance along the jet.…”

Section: Spectroscopymentioning

confidence: 97%

Discovery of a Giant, Highly Collimated Jet From Sanduleak's Star in the Large Magellanic Cloud

Angeloni¹,

Mille²,

Bland-Hawthorn³

et al. 2011

ApJ

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Highly collimated gas ejections are among the most dramatic structures in the universe, observed to emerge from very different astrophysical systems-from active galactic nuclei down to young brown dwarf stars. Even with the huge span in spatial scales, there is convincing evidence that the physics at the origin of the phenomenon, namely, the acceleration and collimation mechanisms, is the same in all classes of jets. Here we report on the discovery of a giant, highly collimated jet from Sanduleak's star in the Large Magellanic Cloud (LMC). With a physical extent of 14 pc at the distance of the LMC, it represents the largest stellar jet ever discovered, and the first resolved stellar jet beyond the Milky Way. The kinematics and extreme chemical composition of the ejecta from Sanduleak's star bear strong resemblance with the low-velocity remnants of SN1987A and with the outer filaments of the most famous supernova progenitor candidate, η Carinae. Moreover, the precise knowledge of the jets distance implies that it will be possible to derive accurate estimates of most of its physical properties. Sanduleak's bipolar outflow will thus become a crucial test bed for future theoretical modeling of astrophysical jets.

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Section: Spectroscopymentioning

confidence: 97%

Discovery of a Giant, Highly Collimated Jet From Sanduleak's Star in the Large Magellanic Cloud

Angeloni¹,

Mille²,

Bland-Hawthorn³

et al. 2011

ApJ

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“…5.3.6 of Skopal 2005). Therefore, indirect methods based on the ratio of nebular line fluxes and/or the presence of the highest ionization states in the spectrum (Mürset & Nussbaumer 1994) are employed to estimate the hot star temperature during active phases. For example, using the ratio of He ii 4686 Å and Hβ line fluxes from the spectra of the symbiotic prototype Z And during its 2000−03 outburst, Sokoloski et al (2006) derived T h = 92 000 ± 20 000 to 160 000 ± 35 000 K. During the smaller, 1997 outburst, both methods indicated an increase in T h to 180 000 K. More trustworthy estimates of T h can be achieved only for non-eclipsing systems with the aid of multiwavelength modelling of the supersoft X-ray/UV SED, which covers the total spectrum emitted by the burning WD.…”

Section: (ṁ) Relationship During Active Phasesmentioning

confidence: 99%

Ionization structure of hot components in symbiotic binaries during active phases

Cariková

Skopal

2012

A&A

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Context. During active phases of symbiotic binaries, an optically thick medium in the form of a flared disk develops around their hot stars. During quiescent phases, this structure is not evident. Aims. We propose the formation of a flared neutral disk-like structure around the rotating white dwarf (WD) in symbiotic binaries. Methods. We applied the wind compression model and calculated the ionization boundaries in the compressed wind from the WD using the equation of photoionization equilibrium. Results. During active phases, the compression of the enhanced wind from the rotating WD can form a neutral disk-like zone at the equatorial plane, while the remainder of the sphere above/below the disk is ionized. The hydrogen column density throughout the neutral zone and the emission measure of the ionized fraction of the wind, calculated for the mass loss rate from the WD, M = 2 × 10 −6 M yr −1 with v ∞ = 2000 km s −1 , are consistent with those derived from observations. During quiescent phases, the neutral disk-like structure cannot be created because of insufficient mass loss rate. Conclusions. Formation of the neutral disk-like zone at the equatorial plane is connected with the enhanced wind from the rotating WD, observed during active phases of symbiotic binaries. This probably represents a common origin of warm pseudophotospheres, indicated in the spectrum of active symbiotic binaries with a high orbital inclination.

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“…However, during June 2015 it was found that AG Peg had brightened from V ∼8.5 to V ∼7.0 over the course of a few weeks (Waagen 2015). Based on the long term light curve shown in Mürset & Nussbaumer (1994) and the records of the amateur astronomer groups mentioned earlier, we con- Figure 1. Photometry of AG Peg over the outburst in the BV I bands and taken from AAVSO data (Kafka 2015).…”

Section: Introductionmentioning

confidence: 99%

Swiftobservations of the 2015 outburst of AG Peg – from slow nova to classical symbiotic outburst

Ramsay

Sokoloski

Luna

et al. 2016

Mon. Not. R. Astron. Soc.

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Symbiotic stars often contain white dwarfs with quasi-steady shell burning on their surfaces. However, in most symbiotics, the origin of this burning is unclear. In symbiotic slow novae, however, it is linked to a past thermonuclear runaway. In June 2015, the symbiotic slow nova AG Peg was seen in only its second optical outburst since 1850. This recent outburst was of much shorter duration and lower amplitude than the earlier eruption, and it contained multiple peaks -like outbursts in classical symbiotic stars such as Z And. We report Swift X-ray and UV observations of AG Peg made between June 2015 and January 2016. The X-ray flux was markedly variable on a time scale of days, particularly during four days near optical maximum, when the X-rays became bright and soft. This strong X-ray variability continued for another month, after which the X-rays hardened as the optical flux declined. The UV flux was high throughout the outburst, consistent with quasi-steady shell burning on the white dwarf. Given that accretion disks around white dwarfs with shell burning do not generally produce detectable X-rays (due to Compton-cooling of the boundary layer), the X-rays probably originated via shocks in the ejecta. As the X-ray photoelectric absorption did not vary significantly, the X-ray variability may directly link to the properties of the shocked material. AG Peg's transition from a slow symbiotic nova (which drove the 1850 outburst) to a classical symbiotic star suggests that shell burning in at least some symbiotic stars is residual burning from prior novae.

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Symbiotic Novae

Cited by 65 publications

References 12 publications

Discovery of a Giant, Highly Collimated Jet From Sanduleak's Star in the Large Magellanic Cloud

Discovery of a Giant, Highly Collimated Jet From Sanduleak's Star in the Large Magellanic Cloud

Ionization structure of hot components in symbiotic binaries during active phases

Swiftobservations of the 2015 outburst of AG Peg – from slow nova to classical symbiotic outburst

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