The 2010 nova outburst of the symbiotic Mira V407 Cyg

Abstract

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

Flash-ionization of pre-existing circumstellar material around Nova Oph 2015

“…A major difference with RS Oph (Skopal et al 2008) and V407 Cyg (Munari et al 2011), is the lack of an even sharper absorption superimposed to the narrow component. This very sharp absorption (FWHM∼15 km sec −1 ) originates is the outer neutral portion of the wind not reached by the initial UV-flash, which is completely absorbed by the gas inner to it.…”

“…There is however a very rare type of nova (∼3% of the total, Williams et al 2014) in which the initial UV flash interacts with dense pre-existing circumstellar material, the prototypes being the recurrent novae RS Oph and V407 Cyg Munari et al 2011). In such systems, the WD orbits -with periods of a few years -within the extended wind of a late type giant companion.…”

Long-term photometric observations of pre-main sequence objects in the field of North America/Pelican Nebula

“…Adding to this, observations of PMS stars are usually made difficult by their faintness in quiescence and by the disturbance from sometimes heavy dust extinction, either surrounding the star or diffuse through the star forming region. Therefore, the rare outbursts of PMS stars always attract considerable interest, especially when they are long lasting, as in the case of new FUor objects (from the name of the prototype of this class, FU Ori), with one of the most recent and spectacular cases being that of HBC 722 = V2493 Cyg (Semkov et al 2010;Miller et al 2011;Munari et al 2010;Leoni et al 2010;Kóspál et al 2011;Armond et al 2011;Green et al 2011).…”

Infrared spectroscopy of the remnant of Nova Sco 2014: a symbiotic star with too little circumstellar matter to decelerate the ejecta

“…While these latter lines grow in prominence, their FWHM however rapidly declines as a consequence of the ejecta being slowed down while trying to expand through the surrounding medium. As an example, during the 2010 outburst of the NwSS V407 Cyg, Munari et al (2011a) measured e-folding times of 4 days for the recombination of the flash-ionized gas and of 3 days for the deceleration of the ejecta.…”

“…Evans et al 2008, Das et al 2006 and V407 Cyg in 2010 (e.g. Munari et al 2011a) are template cases. The powerful initial UV-flash accompanying the TNR onset goes undetected by observers and is lost into surrounding emptiness in the case of classical novae whereas in the NwSS it ionizes the circumstellar gas originating from the wind of the giant.…”