NASA Astronomy Picture of the Day Collection

Infrared Andromeda

This wide, detailed Spitzer Space Telescope view [ http://www.spitzer.…index.shtml ] features infrared light from dust (red) and old stars (blue) in Andromeda, a massive spiral galaxy a mere 2.5 million light-years away. In fact, with over twice the diameter of our own [ http://antwrp.gsfc.…] Milky Way, Andromeda is [ http://www.seds.org…] the largest nearby [ http://www.seds.org…local.html ] galaxy. Andromeda's population of bright young stars define its sweeping spiral arms in visible light images [ http://antwrp.gsfc.…], but here the infrared view clearly follows the lumpy dust lanes heated by the young stars as they wind even closer to the galaxy's core [ http://antwrp.gsfc.…]. Constructed to explore [ http://nedwww.ipac.…Hodge_contents.html ] Andromeda's infrared brightness [ http://coolcosmos.ip ac.caltech.edu// ] and stellar populations, the full mosaic image is composed of about 3,000 individual frames. Two smaller companion galaxies, NGC 205 [ http://antwrp.gsfc.…] (below) and M32 [ http://antwrp.gsfc.…] (above) are also included in the combined fields. The data confirm that Andromeda (aka M31) houses around 1 trillion [ http://kokogiak.com…] stars, compared to [ http://astronomy.sw…] 4 hundred billion [ http://kokogiak.com…] for the Milky Way.

Pauline Barmby (Harvard-Smithsonian CfA [ http://cfa-www.harv…]) et al. [ http://www.spitzer.…moreinfo.shtml ], JPL [ http://www.jpl.nasa…], Caltech [ http://www.spitzer.…], NASA [ http://www.nasa.gov…]

M31

NGC 205

M32

Goddard Space Flight Center (GSFC)

Jet Propulsion Laboratory (JPL)

Atlas

Andromeda

Visible Light

Spitzer Space Telescope

Infrared Array Camera (IRAC)

http://antwrp.gsfc.…

SPD-APOD-ap060609