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
Spectroscopic Binary Stars. Only the motion of one of the stars is needed to deduce the existence of the binary system. (Credit: James Schombert)
When the smaller star partially blocks the larger star, a primary eclipse occurs, and a secondary eclipse occurs when the smaller star is occulted, or completely blocked, by the larger star. (Credit: NASA)
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” http://www.bellaonline.com/articles/art301553....
Quintuplet Cluster. It's most famous star is the Pistol star, the most luminous known star in the Galaxy. On the left is the Hubble image from 1999. On the right is a new one from 2015 - quite a difference in resolving power for the fabulous space telescope.
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
The relative sizes of the Sun, a low mass star, a brown dwarf, Jupiter, and Earth. This is a generalized diagram; J0523 is actually a bit smaller than Jupiter. (Photo credit: NASA/JPL-Caltech/UCB)
Is this the smallest, faintest star? In visible light (arrowed) it's barely visible, but in infrared (inset) it's more easily seen. (Photo: CDA Portal / 2MASS/UMass/IPAC-Caltech/NASA/NSF) Mona Evans, "The Smallest Star in the Universe" http://www.bellaonline.com/articles/art301455.asp
R Coronae Borealis type star. Artist rendering of dust cloud based on observations from the VLT. Variable star that dims erratically when it forms dusty clouds. If the dust is along our line-of-sight it eclipses the star. As the stellar winds blow the dust away, the star reappears. (Credit: ESO)
Arches Cluster. IR image taken by the Hubble Space Telescope. The cluster is the most crowded place in the Milky Way. A sphere 4.4 light years in radius would hold the Sun & our nearest neighbor α Centauri. In the Arches Cluster a region that size would hold over 100,000 stars. (Credit: ESA, NASA)
The triple star system Polaris (Alpha Ursae Minoris), as seen by the Hubble Space Telescope. Mona Evans, "Polaris - Facts for Kids" http://www.bellaonline.com/articles/art301252.asp
The 26,000-year cycle of precession as seen from near the Earth. The current north pole star is Polaris (top). In about 8,000 years it will be the bright star Deneb (left), and in about 12,000 years, Vega (left center). The Earth's rotation is not depicted to scale – in this span of time, it should rotate over 9 million times. Mona Evans, "Ecliptic and Equinoxes" http://www.bellaonline.com/articles/art20530.asp
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.
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)
GRO J1655-40, binary star system 11,000 light years away in the constellation Scorpius. It consists of a star about twice the mass of the Sun & a black hole of about seven solar masses. The artist's vision shows matter drawn from the normal star by gravity & swirling toward the black hole. A wind of material is also escaping from the black hole's accretion disk. (Illustration: M. Weiss (CXC), NASA) Mona Evans, "Scorpius the Scorpion", http://www.bellaonline.com/articles/art301069.asp
Butterfly Cluster (M6 / NGC 6405). Bright open star cluster in the constellation Scorpius. Its popular name reflects the butterfly shape you can see in this picture. About eighty stars have been identified, but the cluster probably has over three hundred, mostly hot blue stars. (Image Credit: N.A.Sharp, Mark Hanna, REU program/NOAO/AURA/NSF) Mona Evans, "Scorpius the Scorpion", http://www.bellaonline.com/articles/art301069.asp
Compact center of globular cluster Messier 70 in the constellation Sagittarius. Quarters are always tight in globular clusters, where the mutual hold of gravity binds together hundreds of thousands of stars in a small region of space. (Credit: ESA Hubble & NASA) Mona Evans, “Sagittarius the Archer” http://www.bellaonline.com/articles/art300844.asp
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
Light curve of binary star Kepler-16. (Image: NASA) This an example of a a type of variable star known as an eclipsing variable. Algol is the classic example of such a star, but Lambda Tauri is also seen nearly edge on like this. Lambda Tauri is a triple system and a third star orbits the binary. Mona Evans, "Taurus the Bull" http://www.bellaonline.com/articles/art300646.asp
M44: The Beehive Cluster (Image Credit & Copyright: Bob Franke)
Comparing the sizes of the planets, then comparing bigger and bigger and yet bigger stars. Mona Evans"How Big Are the Biggest Stars" http://www.bellaonline.com/articles/art300366.asp
Hypergiant Size comparison between the Sun and VY Canis Majoris, a hypergiant which is one of the largest known stars. Mona Evans"How Big Are the Biggest Stars" http://www.bellaonline.com/articles/art300366.asp
A STAR'S BIRTH AND DEATH