Image credit & copyright: NASA/ESA Hubble Space Telescope.
Named after its discoverer Arthur Hoag, Hoag’s Object is as strange as it is beautiful. Located (sit down for this one) 600 million light years away, when Arthur Hoag discovered this galaxy in 1950 he wasn’t sure if the faint smudge he was seeing was a peculiar galaxy or a planetary nebula. Turns out, he had discovered one of the most beautiful and unique galaxies we know of today.
In the main ring of this galaxy, we can see the blue hue of young stars indicating that this galaxy still has some star formation taking place. In the core we see the yellow sign of ancient stars that have made their way to the center. The usual hypothesis of how these ring galaxies come to be include galactic collisions or now vanished bars, but truth is, we don’t fully understand them yet.
Interestingly enough, if you peer through the ring to about the one o’clock position there appears to be a second ring galaxy (cataloged as SDSS J151713.93+213516.8) tens of millions of light years beyond.
NAME: Hoag’s Object.
WHAT IS IT?: Ring galaxy with another ring galaxy (SDSS J151713.93+213516.8) within it, far beyond.
HOW FAR AWAY IS IT?: 600 million years and receding at 7,916 mi. (12,740 k) per second.
HOW BIG IS IT?: Roughly 120,000 light years in diameter.
APPARENT MAGNITUDE: A very dim 16.
WHERE IS IT? (General): Constellation Serpens (The Serpent).
WHERE IS IT? (Exact RA/Dec J2000): RA 15h 17m 14.4s / Dec +21° 35′ 08″.
Hubblesite News Center page for this image: http://hubblesite.org/newscenter/archive/releases/2002/21/image/a/