2013-08-30 21:28 UT
200mm f5 newtonian, unguided
4×30s ISO 800, darks
Canon EOS 350D modded, Astronomik CLS
Captured in APT, Processed in Nebulosity, PS CS5
Discovered 14 Aug 2013 by Koichi Itagaki of Yamagata, peaked at mag. 4.5.
It’s about 13,000 light years away. Was originally quite blue but is now much redder – this is what sometimes happens as novae evolve.
From Sky & Telescope
The nova was discovered by Koichi Itagaki of Yamagata, Japan, in an image taken at 14hhUniversal Time (2 p.m. EDT) on August 14th. It was not present in a photo that he took the previous day. Here is the announcement from the IAU’s Central Bureau for Astronomical Telegrams. The star was apparently 17th magnitude before erupting, so it brightened roughly 100,000-fold to its peak on August 16th.
A classical nova happens in a special kind of tightly-orbiting binary star system: one where a relatively normal star pours a stream of hydrogen onto the surface of a companion white dwarf. When the layer of fresh hydrogen on the white dwarf’s surface grows thick and dense enough, the bottom of the layer explodes in a runaway hydrogen-fusion reaction — a hydrogen bomb in the shape of a thin shell roughly the size of Earth. The underlying white dwarf remains intact, and as new hydrogen builds up, the process may repeat in a few years to tens of thousands of years.