Astronomy Picture of the Day: 11/15/13 - NGC 660

Among all sorts of galaxies that have varying shapes and colors, the ring galaxies are still the most odd of them all. This is one example, the Polar Ring galaxy, which is formally known as NGC 660. The galaxy is only about half the size of the Milky Way, measuring in at about 40,000 light-years across, but despite its quaint size, it"s an area of intense stellar activity, churning out thousands of baby stars regularly. The light from said stars is just now reaching us after their long journey of 20 million light-years.

The strange shape of the Polar Ring galaxy (and others that are similar to it) can be attributed to close encounters between two neighboring galaxies. Some of these encounters result in actual collisions, where typically, the smaller galaxy pierces through the heart of the larger one, with lots of stellar material (like gas and dust) blown about, creating a large orbiting ring of gas and dust (Shockwaves then trigger furious rates of star production within the galaxy. This star formation activity can see seen if you look closely at the reddish regions).

Arp 336, or the Helix Galaxy, is a different example of a polar ring galaxy. Credit: Ken Crawford, Rancho Del Sol Observatory

Despite us having a slew of similar-looking galaxies that have been designated as "polar ring galaxies," this one is unique of its kind. Typically, the ring of material is perpendicular to the plane of the central galaxy. Instead, this one"s ring and shape are just a bit off-kilter. (Technically classifying it as a late-type lenticular galaxy)

References & Additional Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-111513-ngc-660/

Image Credit: Gemini Observatory, AURA, Travis Rector (Univ. Alaska Anchorage)