Hoags Object: A Strange Ring Galaxy
Explanation:
Is this one galaxy or two?
This question came to light in 1950 when astronomer
Art
Hoag
chanced upon this unusual extragalactic object.
On the outside is a
ring dominated by bright blue stars,
while near the center lies a ball of much redder stars
that are likely much older.
Between the two is a
gap that appears almost completely dark.
How
Hoag's
Object
formed remains unknown, although similar objects
have now been identified and collectively labeled as a form of
ring galaxy.
Genesis hypotheses include a
galaxy collision
billions of years ago and
perturbative gravitational interactions
involving an unusually shaped core.
The
above photo taken by the
Hubble Space Telescope
in July 2001 reveals unprecedented details of
Hoag's Object and may yield a
better understanding.
Hoag's Object spans about 100,000
light years and lies about 600 million
light years away toward the
constellation of
Serpens.
Coincidentally, visible in the gap
(at about one o'clock) is yet another
ring galaxy that likely lies
far in the distance.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
