Type: Star Also known as: GSC 04822-00039
Considering the staggering number of star in our galaxy alone, it takes a lot for one of them to get noticed. Take V838 Mon here - a red variable star lying some 20,000 light years away in the Monoceros (Unicorn) constellation, and until the end of the 20th century it was unknown to us bumbling humans, but then it did something spectacular, not to mention unexpected, to grab our attention.
For reasons that are still unclear, in 2002 the then-unnamed V838 Mon underwent a major outburst which, as well as causing a substantial increase in its luminosity and mass, also ejected an enormous dust cloud which expanded rapidly, giving excited astronomers a spectacular display thanks to a remarkable series of images captured by the Hubble Space Telescope.
Puzzled astronomers are still struggling to work out exactly why the star (which is actually part of a binary system) had such a hissy fit - there are currently at least six hypotheses - but whatever the reason, the swirly gases are still lighting up the region, the star itself continues to shin on in all its deep redness, and the photos have made it one of the most recognisable astronomical objects of all.
Click here to see an amazing time-lapse video of the gas cloud expansion.