Astronomy Picture of the Day: 01/04/14 - The Fireworks Galaxy

To start off 2014 right, this is the Fireworks Galaxy, aptly named given its brilliance. NGC 6946, as it is formally known as, lies about 10 million light-years from Earth in the constellation of Cepheus. When it was originally discovered by Sir William Herschel, the galaxy was widely believed to be a member of our local group, which is made up of over 50 galaxies, including several other dwarf-galaxies. It wasn"t until years later that astronomers discovered that the reddening seen enveloping the galaxy was from interstellar dust grains, obscuring our view (instead of red-shift).

Speaking of red, the applicable areas are star forming regions, teeming with new-life -- while the blue bits are actually celestial members of our own galaxy, which are obstructing our view of NGC 6946. Interestingly, several new supernova remnants have been discovered each year for the last 60 lurking within NGC 6946"s spiral arms. This is very unusual, as it is normal to only witness one supernova blast every 30 years in galaxies similar to our own.

References & Further Reading: http://www.fromquarkstoquasars.com/apod-fireworks-galaxy/

Image Credit: NASA/JPL-Caltech/R. Kennicutt (U. of Ariz./Inst. of Astr., U. of Cambridge) and the SINGS Team

Astronomy Picture of the Day: 12/05/13 – E0102

In one of the most beautiful images ever taken of the Small Magellanic Cloud (SMC), Hubble reveals a greenish-blue shell of debris from a massive star that went supernova. The remnant, which is know as "E0102" for short (more formally known as 1E0102.2-7219) -- is located approximately 210,000 light-years away from Earth in the satellite galaxy of the Milky Way. (Locally, it"s about 50 light-years away from N 76, a star-forming region found in the outer trenches of the SMC).

The stark contrast in coloring in this composite image can be attributed to different elements located within the star forming region of the Small Magellanic Cloud. N 76 is primarily composed of glowing hydrogen emissions. Whereas, E0102 is an oxygen-rich environment that has a startling absence of hydrogen and helium (key components in star formation). It is believed that the abundance of oxygen in the surrounding environment can be attributed to a very large, old and unstable Wolf-Rayet star. Over the course of the last hundreds of thousands of years, the star lost most of its hydrogen envelope through stellar winds. Said material then carried off the outer-most shell of the star, leaving behind oxygen once the star exploded. Shortly after, the core contracted to become a neutron star.

As far as the age of the remnant is concerned, it is relatively young compared to many of its similar counterparts. The original supernova blast was estimated to have taken place about 2,000 years ago and is just now starting to expand into the interstellar medium. (This would essentially mean that the explosion occurred more than 230,000 years ago. It just took so long for the light from the event to arrive on Earth)

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-120513-e0102/

Image Credit: NASA, ESA and the Hubble Heritage Team STScI/AURA