The central region of the small galaxy NGC 1705 blazes with the light of thousands of young and old stars. Astronomers call NGC 1705 a dwarf irregular, that is, a small galaxy lacking regular structure. Knowing how dwarf irregular galaxies evolve tells us a lot about galaxy formation and evolution.
Dwarf irregulars are similar in many ways to very young galaxies, but they are much nearer and easier to study. These galaxies seem to have consumed only a tiny part of their reservoir of gas. Their stars have a much lower fraction of heavy elements than does the Sun. Astronomers therefore think that only a few generations of stars have formed there over time. NGC 1705's age, its irregular shape, and proximity all make it an excellent source of knowledge about galaxy formation and evolution.
This image was taken in March 1999 and November 2000 by an international science team led by Monica Tosi at Italy's National Institute of Astrophysics (INAF) at the Osservatorio Astronomico di Bologna. Other team members include Alessandra Aloisi (JHU), Mark Clampin (STScI), Laura Greggio (INAF, Osservatorio Astronomico di Padova), Claus Leitherer and Antonella Nota (STScI). Hubble's Wide Field Planetary Camera 2 observed the galaxy in ultraviolet, blue, visible, and infrared light. Although not included in this image, NICMOS (Near Infrared Camera and Multi Object Spectrometer) observations were also made of the galaxy's central core.