Peter Doig Exhibition Poster

A nova out of the ordinary

On March 10 some Japanese observers detected an explosion in the variable star V407 Cygni. The strange thing was the intensity of the blast, which reached a maximum brightness of 7.4, when often remain in the 13 sleep.

V407 Cygni is a symbiotic variable. Symbiotic star is called a binary star in which coexist with a very sharp contrast in their spectral types (ie, their surface temperatures). This difference is evident in their spectra, which were impossible to read until it was determined that responded to the combination of those for each component of a dual system. Similarly, in a symbiotic variable shows a very long period of revolution, which means that the hotter component (and small and compact) revolves around a star enough massive so you have to do it at a distance take years to complete one revolution. It should be a big star and cold, a condition that meets a red giant.

symbiotic variables are strange in their behavior, show regular variations similar to those of a Mira variable (which are variations of the red giant component, acting as such type of variable), can present occasional eclipses when the plane of rotation of the system is a suitable inclination, or, without a clear periodicity, flare or outburst "very similar to lso given in the so-called cataclysmic variables, by mechanisms quite similar.

The symbiotic are kind of all-in-one variable stars: pulsating, tiling, eclipsing and eruptive, and herein lies part of its interest in astronomical objects.

And it does not end here, the symbiotic also can erupt in a violent way, with much wider than a regular pop. It is an explosion similar to those of a classical nova, and is considered as a category of nova, we will refer to this as a symbiotic nova.

And this is what has happened to V407 Cygni. Around its compact hot component has been an accumulation of hydrogen gas to achieve higher levels of density and pressure conditions found to begin nuclear fusion that leads to Helio. This fusion takes place in an abrupt and explosive, which is manifested in the explosion of nova.

In the case of not knowing the progenitor of the nova can be identified as symbiotic by the length of the burst and its own spectral characteristics. But in this case we know the system has occurred, which is a symbiotic variable more or less well known.

From now until later this year is expected to V407 Cyg remains on a scale accessible to visual observation with telescopes modest. Can be an object of interest in the summer observations to be located in this constellation as typical summer as Swan.