There has been a new development over the past couple of days. A previously non distinct star near the constellation Delphinus has literally exploded in luminosity very recently.
The sudden brightening of this star is called a nova, and this one is named Nova Delphini 2013. A nova is the result when a type of star, called a white dwarf, accumulates hydrogen on it's surface. The hydrogen ignites and causes an uncontrolled nuclear chain reaction and explodes in a powerful outburst. White dwarves are stellar remnants. They are the last phase in the stellar life cycle when a star does not have sufficient mass to go supernova and become a neutron star or black hole. Most stars will become a white dwarf, including our own Sun.
Most, if not all novae, are though to happen in binary star systems that include a white dwarf and a larger companion star. If the stars are very close, the strong gravitational influence of the dwarf can rip off stellar material from the companion and deposit it on it's surface. This material becomes compressed and heated until it undergoes nuclear fusion. This reaction can become unstable and lead to a massive explosion on the dwarf's surface. This is what causes the star to become much brighter than normal.
A nova should not be confused with a supernova. A supernova results when the entire star explodes, whereas a nova is just a explosion on the surface. A white dwarf involved with a nova will still be intact and can repeat the process many times. In some cases, a white dwarf can accrete too much stellar material and explode as a type of supernova.
Currently Nova Delphini 2013 is bright enough to be seen with the naked eye in dark sky areas. It's brightness is between magnitude +4 and +5 and is steadily brightening. For more information about this nova and how to find it in the sky, follow this link:Bright New Nova In Delphinus — You can See it Tonight With Binoculars
Finally, here is an image of Delphini 2013 that I've recently taken:
Wow it's been a while since I've put up a new post, been busy with a bunch of stuff over the past few months. I hope to be able to start posting on here a lot more often, we have some cool astronomy happenings coming up later this year. More on that in a later post.
For now lets focus on what's going on in the near future: the Perseid meteor shower. It's that time of year again for one of the most spectacular meteor shows of the year, perhaps second only to the December Geminids. The Perseids run from mid July to late August, and peak on August 11-13. They originate from the tail remanents of Comet Swift-Tuttle and are notable for producing very bright meteor streaks in the sky. The Perseids appear to radiate from the constellation Perseus, from which they get their name, and the expected hourly rate this year is anywhere from 60 to 100 per hour.
So when and where to look? Start this weekend on the night of the 11th/morning of the 12th. The young crescent moon will have set before midnight, so begin your search then. The radiant in Perseus will be low in the sky toward the northeast, but the meteors can and will appear from anywhere in the sky. The best times to watch will be in the early morning hours of the 12th and 13th.
Have fun and get out your cameras. You might be able to get a quick pic of a meteor. Because it is impossible to anticipate when and where a meteor will appear, you will have to take many pictures over a long period and hope to capture one. Use a wide angle lens or set your zoom to it's widest point. Use a tripod or lay your camera on a flat surface pointing up. Set it to take several 10-20 second exposures at a high ISO setting. Afterwards, you can look though your images and hopefully you'll have a nice meteor surprise!
