A new star!

Over the last few days, there's been a new star in our skies! Well, it appears as such anyway.

Discovered by amateur astronomer Koichi Itagaki on the 14th of August 2013, the attractively named PNVJ20233073+2046041 (now renamed Nova Delphini 2013 - thankfully) was spotted near the borders between the constellations Delphinus, Vulpecula and Sagitta. Rather than a new star, however, Nova Delphini 2013 is a much rarer object.

Nova Delphini 2013 located at RA 20:23:30.73 DEC +20:46:04.1 with DSS data from the same region (prior to Nova) inset.

Deep sky images show a very dim star, around +17 in magnitude, at the precise location of our Nova. Most likely, this is the progenitor of this event.

A nova takes place where a large giant star and a small white dwarf are in orbit around each other. Due to the intense gravitational forces arising from the massive density of the dwarf and the proximity of the two stars, material becomes torn away from the larger of the pair and begins to accrete upon the surface of the white dwarf. As this material collects, its temperature and pressure steadily rises until it reaches a critical point, at which it erupts in a cataclysmic thermonuclear explosion. This violent outburst causes the dwarf to increase dramatically in brightness, in this case by about 25,000 times so far. 

An artist's impression of a nova in action.

How bright this will become is anyone's guess, and the nova may endure for days and weeks to come.

Unlike in a supernova explosion, the white dwarf is not destroyed in the event, and is likely to give birth to another nova, and possibly many more, in the millennia to come. Eventually though, the tiny white dwarf may succumb and be destroyed, causing a Type Ia supernova which may be brighter than all of the stars in the milky way combined!