Ooh what a lovely big one!

My image shows the rear end or tail of
 the constellation Cygnus the Swan. 

It would be quite rude to leave the constellation Cygnus without mentioning Alpha Cygnus otherwise known as Deneb. Deneb can be seen currently riding high in the eastern sky from about 10.00pm British Summer time.

Deneb, along with Vega in the constellation Lyra and Altair in the constellation Aquila, form the asterism known as the Summer Triangle. The Summer Triangle is very easy to identify if you look south to east, as the three stars Deneb, Vega and Lyra are very bright and form its three corner points.  If you have a clear night, why not try to identify these three stars?

Deneb is a blue-white supergiant star, the nineteenth brightest star in the night sky, estimated to be between 54,000 and 196,000 times more luminous than our Sun.  It is thought to be 26,000 light years distant from our Solar System.  Deneb is a big star with a diameter some 100-200 times and a mass some twenty times that of the Sun.

All in all Deneb is 'a big one' alright but losing mass through its powerful solar wind at a prodigious rate, approximately 100,000 times faster than our Sun.  At 8500 degrees Kelvin, Deneb's surface temperature is also much hotter than the Sun .  Deneb has finished fusing hydrogen in its core and after a relatively brief existence as a red supergiant and in a few million years time, will explode in a catastrophic core collapse supernova.  That will be a big one too!

Hertzsprung-Russell Diagram

You can see Deneb at the top of the Hertzsprung-Russell Diagram.  As Deneb ages it will move to the right following a path taken before it by the star Betelgeuse in the constellation Orion.

Betelgeuse will be visible from the UK in late autumn, winter and early spring.

Credits:Wikipedia, NASA, ESA, Flickr and Astrometry Solver.

The Summer Triangle