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.
At 17 million light-years away, the individual stars of the galaxy NGC 1705 are out of range of all but the sharp eyes of the NASA/ESA Hubble Space Telescope.
NGC 1705 is an ideal laboratory to conduct investigations on the history of star formation. Young, blue, hot stars are strongly concentrated toward the galaxy's centre. Older, red, cooler stars are more spread out. This galaxy has been forming
new stars throughout its lifetime, but a burst of star-formation activity occurred as recently as 26 to 31 million years ago. This 'starburst' is responsible for many of the young stars on the outskirts of this galaxy's core as well as the central giant star cluster.
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.