An extremely dense, old star known as a white dwarf star exploded on January 14, 2014, but wasn’t noticed until a week later. Luckily this occurred in a galaxy known as M82, about 12 million light years away. If it had occurred in our own Milky Way galaxy anywhere near the sun, we would already have been obliterated.

This exploding star, known as a supernova, designated SN 2014J, is a type 1a supernova, a kind that helps astronomers measure the size and expansion rate of the universe. The galaxy it is located in, M82, is an irregular galaxy, not the more common spiral type. It has lots of dust and hydrogen gas and active star formation occurring in its center. The first image is a picture of M82 I took in June of 2012

This galaxy can be seen in a modest telescope near the Big Dipper. This photo was taken well before the explosion.

The second image is a picture of M82 I took February 23, 2014:

 The new star is at the point where the two red lines would intersect. As you can see, it is brighter than anything else in the whole galaxy, thus representing a massive amount of energy output. To give you a sense of the apparent size of this galaxy, it’s length would fit about 6 times across the full moon. So it appears much smaller, and about 100 million  times fainter that the full moon.

Many people think the stars never change, but supernovas are an exception. They can appear almost instantly, sometimes outshining all the other stars in a galaxy combined, then gradually fade over several years.

Keep looking up,

Carter Mehl,

(Sometime) Resident Astronomer,

Lookout Observatory