Messier Objects Project
By Katie Stewart, March 15, 2013.
-Omega, Swan, Horseshoe, or Lobster Nebula.
-Type: nebula, H II region with cluster.
-Distance: between 5,000 and 6,000 light years from Earth
-Apparent Magnitude: +6.0
-Mass: estimated to be 800 solar masses
Nebulae are formed from supernovae debris and the atmospheres of cool giant stars. It's one of the youngest known clusters at the age of about 1 million years. This nebula is a stellar nursery. There is an open cluster of 35 stars, but there are closer to 800 total stars in M17.
Miles, Kathy. "Sagittarius the Archer." Sagittarius the Archer. N.p., n.d. Web. 15 Mar. 2013.
Nemiroff, Robert. "Astronomy Picture of the Day." APOD: 2012 May 6. NASA, 6 May 2012. Web. 15 Mar. 2013.
"Omega Nebula." Wikipedia. Wikimedia Foundation, 03 Dec. 2013. Web. 15 Mar. 2013.