Home
 Space Photos - SEARCH
 Frequently Asked Questions
 New
 Hubble - APOD Selections
 Earth from Space Photos
 Robert Gendler Photos
 Apollo Gemini Mercury Photos
 Top 50
 Space Shuttle - Space Station Photos
 Recent Requests
 Spitzer Photos
 More Hubble Photos
 Astronaut Crew Portraits
 Chandra Catalog
 Planet Photos
 Comets - Asteroids
 Other Astronomy Photos
 Sun Photos
 Links I Use
 Gift Certificates
 Videos
 
 Show Order
 Help
 Index
 



Click to enlargeHubble Sagittarius Dwarf Galaxy Photo

Buy this Sagittarius Dwarf Galaxy space photo.
High quality Hubble picture, slide, or Duratrans backlit transparency. NASA photograph H2004-31b. Wide variety of sizes.

Click to see selection as Astronomy Picture of the Day (APOD) - November 16, 2004


This new image from the Hubble Space Telescope shows a small galaxy called the Sagittarius dwarf irregular galaxy, or "SagDIG" for short. SagDIG is relatively nearby, and Hubble's sharp vision is able to reveal many thousands of individual stars within the galaxy.

The brightest stars in the picture (easily distinguished by the spikes radiating from their images, produced by optical effects within the telescope), are foreground stars lying within our own Milky Way galaxy. Their distances from Earth are typically a few thousand light-years. By contrast, the numerous faint, bluish stars belong to SagDIG, which lies some 3.5 million light-years (1.1 Megaparsecs) from us. Lastly, background galaxies (reddish/brown extended objects with spiral arms and halos) are located even further beyond SagDIG at several tens of millions parsecs away.

As their name implies, dwarf irregular galaxies are unlike their spiral and elliptical cousins, because of their much smaller physical size and lack of definite structure. Using Hubble, astronomers are able to resolve dwarf irregular galaxies that are at very large distances from Earth, into individual stars. By examining properties of the galaxy, such as distance, age and chemical composition, the star formation history of the whole galaxy is better understood, and reveals how, where, and when active star formation took place.

The main body of SagDIG shows a number of star-forming complexes that cover an appreciable fraction of the galaxy surface area. The presence of on-going star formation in a gas-rich galaxy such as this makes SagDIG an excellent laboratory where scientists can test present-day theories of what triggers star-formation in galaxies (without companions) and how this propagates throughout the galaxy.

November 11, 2004
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
Acknowledgment: Y. Momany (University of Padua)


H2004-31b
Select Size: 
Surface: 
Follow SpaceImages on Twitter
Want to receive email updates? Click here.
Questions or Comments? Click here to send e-mail.