Symbiotic stars on Asiago archive plates. II

Munari, U.; Jurdana-Šepić, Rajka

doi:10.1051/0004-6361:20020201

Cited by 15 publications

(14 citation statements)

References 31 publications

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“…1 could appear in conflict with the expected underlying pulsation cycle of the Mira. Indeed, the pulsation of the latter is known to be highly variable from cycle to cycle (K98; Munari & Jurdana‐Šepić 2002), with puzzling sharp minima occurring at various pulsation phases (Kiziloglu & Kiziloglu 2010; some of them are visible also in the light curve of Fig. 1 in 2007 and 2009), and that could be related to the unusual nature of the Mira in V407 Cyg.…”

Section: Resultsmentioning

confidence: 99%

The 2010 nova outburst of the symbiotic Mira V407 Cyg

Munari

Joshi

Ashok

et al. 2011

Monthly Notices of the Royal Astronomical Society: Letters

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108

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The nova outburst experienced in 2010 by the symbiotic binary Mira V407 Cyg has been extensively studied at optical and infrared wavelengths with both photometric and spectroscopic observations. This outburst, reminiscent of similar events displayed by RS Oph, can be described as a very fast He/N nova erupting while being deeply embedded in the dense wind of its cool giant companion. The hard radiation from the initial thermonuclear flash ionizes and excites the wind of the Mira over great distances (recombination is observed on a time scale of 4 days). The nova ejecta is found to progressively decelerate with time as it expands into the Mira wind. This is deduced from line widths which change from a FWHM of 2760 km/s on day +2.3 to 200 km/s on day +196. The wind of the Mira is massive and extended enough for an outer neutral and unperturbed region to survive at all outburst phases.Comment: MNRAS Letter, in pres

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Section: Resultsmentioning

confidence: 99%

The 2010 nova outburst of the symbiotic Mira V407 Cyg

Munari

Joshi

Ashok

et al. 2011

Monthly Notices of the Royal Astronomical Society: Letters

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108

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“…From broadband optical and near-infrared photometry, Kolotilov et al (1998) confirmed the period of 745 days and found a Mira-like K-band amplitude of 1 mag. Optical and near-IR light curves from 1970 to 2000 were presented by Munari & Jurdana-Šepić (2002). They found periods, which are a function of color, in the range 745 to 756 days.…”

Section: The Miramentioning

confidence: 99%

Infrared Spectroscopy of Symbiotic Stars. Ix. D-Type Symbiotic Novae

Hinkle

Fekel

Joyce

et al. 2013

ApJ

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Time-series spectra of the near-infrared 1.6 μm region have been obtained for five of the six known D-type symbiotic novae. The spectra map the pulsation kinematics of the Mira component in the Mira-white dwarf binary system and provide the center-of-mass velocity for the Mira. No orbital motion is detected in agreement with previous estimates of orbital periods 100 yr and semimajor axes ∼50 AU. The 1-5 μm spectra of the Miras show line weakening during dust obscuration events. This results from scattering and continuum emission by 1000 K dust. In the heavily obscured HM Sge system the 4.6 μm CO spectrum formed in 1000 K gas is seen in emission against an optically thick dust continuum. Spectral features that are typically produced in either the cool molecular region or the expanding circumstellar region of late-type stars cannot be detected in the D-symbiotic novae. This is in accord with the colliding wind model for interaction between the white dwarf and Mira. Arguments are presented that the 1000 K gas and dust are not Mira circumstellar material but are in the wind interaction region of the colliding winds. CO is the first molecule detected in this region. We suggest that dust condensing in the intershock region is the origin of the dust obscuration. This model explains variations in the obscuration. Toward the highly obscured Mira in HM Sge the dust zone is estimated to be ∼0.1 AU thick. The intershock wind interaction zone appears thinnest in the most active systems. Drawing on multiple arguments masses are estimated for the system components. The Miras in most D-symbiotic novae have descended from intermediate mass progenitors. The large amount of mass lost from the Mira combined with the massive white dwarf companion suggests that these systems are supernova candidates. However, timescales and the number of objects make these rare events.

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“…The magnitude of KT Eri was then visually estimated against the comparison sequence. This method has been used extensively and successfully tested to reconstruct the photometric history of symbiotic stars and novae from several thousand plates in the Asiago plate archive (e.g., Munari et al 2001;Munari & Jurdana-Šepić 2002;Jurdana-Šepić & Munari 2010). For KT Eri, we used the same UBVR c I c comparison sequence, calibrated against the Landolt (1983Landolt ( , 1992 standard stars, as used in the extensive BVRI CCD photometric monitoring of the 2009 outburst performed by the ANS Collaboration , discussed in a forthcoming paper.…”

Section: Data Summarymentioning

confidence: 99%

Historical light curve and search for previous outbursts of Nova KT Eridani (2009)

Jurdana-Šepić

Ribeiro

Darnley

et al. 2011

A&A

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Context. Nova Eridani (2009) caught the eye of the nova community due to its fast decline from maximum, which was initially missed, and its subsequent development in the radio and X-ray wavelengths. This system also exhibits properties similar to those of the much smaller class of recurrent novae; themselves potential progenitors of type Ia supernovae. Aims. We aim to determine the nature and physical parameters of the KT Eri progenitor system. Methods. We searched the Harvard College Observatory archive plates for the progenitor of KT Eri to determine the nature of the system, particularly the evolutionary stage of the secondary. We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale. Furthermore, by comparing the colours of the quiescent system on a colour−magnitude diagram we may infer the nature of the secondary star. Results. We identified the progenitor system of KT Eri and measured a quiescent magnitude of B = 14.7 ± 0.4. No previous outburst was found. However, we suggest that if the nova is recurrent it should be on a timescale of centuries. We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary. The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in, or ascending, the Red Giant Branch. A second period is evident at 376 days which has a sinusoidal like light curve. Furthermore, the outburst amplitude of ∼9 mag is inconsistent with those expected for fast classical novae (∼17 mag) which may lend further support for an evolved secondary. Conclusions. We investigated the probable recurrent nova KT Eri for which we suggest an inter-outburst period of order centuries and an evolved secondary. This may suggest that there is a whole range of possible inter-outburst periods in between the "typical" classical and recurrent novae nomenclature. Archival searches are an excellent tool in order to investigate the nature of astrophysical objects, in order to determine the nature and physical parameters.

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Symbiotic stars on Asiago archive plates. II

Cited by 15 publications

References 31 publications

The 2010 nova outburst of the symbiotic Mira V407 Cyg

The 2010 nova outburst of the symbiotic Mira V407 Cyg

Infrared Spectroscopy of Symbiotic Stars. Ix. D-Type Symbiotic Novae

Historical light curve and search for previous outbursts of Nova KT Eridani (2009)

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