Alpha Capricorni - optical double star. They look close together, but are nearly 600 light years apart. The image was produced by WikiSky's image cutout tool out of DSS2 (Digitized Sky Survey) data. Mona Evans, "D Is for Double Stars" http://www.bellaonline.com/articles/art301605.asp
Star cluster Westerlund 2. Hubble 25th anniversary image. Young stars flaring to life resemble an exploding shell in a fireworks display. The giant star cluster is only about two million years old, but contains some of the brightest, hottest and most massive stars ever discovered. The red dots are a rich population of forming stars that are still wrapped in their gas and dust cocoons. (Credit: NASA/ESA Hubble Space Telescope)
Globular Cluster M22. It contains over 100,000 stars that formed together and remain gravitationally bound. The cluster orbits the center of the Milky Way. Globular clusters are very old, close to the age of the Universe. (Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT) Mona Evans, “Sagittarius the Archer” http://www.bellaonline.com/articles/art300844.asp
Coronet Cluster in Corona Australis. (Credit: X-ray: NASA/ CXC/CfA/ J.Forbrich et al.; Infrared: NASA/SSC/CfA/IRAC GTO Team) X-rays from young stars & infrared light from stars & cosmic dust are combined in a false color image. The small star grouping is the Coronet Cluster. The view was produced using data from the orbiting Chandra Observatory (x-ray) and the Spitzer Space Telescope (infrared). Mona Evans, “The Starry Crowns – Corona Australis”…
47 Tucanae, located in the constellation Tucana, is the second largest known globular cluster. Here it's shown in a digital art work by Felix Cheung. It's one of a set of screen savers based on the Southern birds constellations. Mona Evans, "Exotic Creatures of the Southern Sky" http://www.bellaonline.com/articles/art301200.asp
Globular cluster IC 4499 in the southern constellation Apus (Bird-of-paradise). (credit: NASA/ESA Hubble Space Telescope) The stars in this cluster formed at the same time and gravity pulls its large mass together into a spherical shape.
The relation between size and temperature at the point where stars end and brown dwarfs begin (based on a figure from the publication) Image credit: P. Marenfeld & NOAO/AURA/NSF. Mona Evans, "The Smallest Star in the Universe" http://www.bellaonline.com/articles/art301455.asp