Everybody knows Andromeda, the big sister of the Milky Way, who lives right next door. But not as many are familiar with our home galaxy's little sister - the Triangulum galaxy.
Today Triangulum gets her star turn at last, in a high-resolution digital image from the 21-foot (6.5-meter) MMT Observatory in Arizona.
Caldwell, McLeod and Szentgyorgyi / SAO |
| The Triangulum galaxy shines in shades of orange, pink and blue in this image from MMT Observatory's Megacam. Click on the image for higher-resolution views. |
The newly released photograph shows Triangulum, the smallest of the three spiral galaxies in our celestial neighborhood, in shades of orange-brown, pink and blue. The orange areas are patches of interstellar dust, and the blue spots signify young stars, while the pinkish structures are filaments of hydrogen gas in regions of active star formation.
Today's image advisory from the Harvard-Smithsonian Center for Astrophysics takes particular note of the pink nebula at upper left in the image, known as NGC 604. This nebula is analogous to the Milky Way's famous Orion Nebula, but stretches much wider (1,500 light-years as opposed to the Orion Nebula's 30 light-years or so) and is lit from within by more than 200 hot young stars.
Triangulum, also known as M33, is 2.4 million light-years from Earth in the northern constellation of the same name, wedged between Perseus and Andromeda. It spans about twice the diameter of a full moon in the night sky, but its light is so diffuse that it's hard to spot with the unaided eye. (This guide helps you find it.)
The galaxy is also a relative lightweight: It holds the equivalent of 10 billion to 40 billion suns, compared with the Milky Way's tally of 200 billion to 400 billion suns, and Andromeda's heft of more than a trillion suns.
"Triangulum is not a colossal giant like the Milky Way or Andromeda," said Nelson Caldwell, an astronomer at the Smithsonian Astrophysical Observatory in Cambridge, Mass. "But it has a charm and a beauty of its own that belies its junior citizen status."
Today's snapshot is one of the first produced by the MMT Observatory's new Megacam instrument. The camera was developed under the direction of Smithsonian astronomer Brian McLeod, and consists of 36 imaging chips, each capable of recording 9 million pixels. That makes Megacam one of the world's largest digital cameras.
"Megacam is like a turbocharged household digital camera," Caldwell said. "While a typical digital camera might have 8 or 9 megapixels, Megacam has 340 megapixels."