An Extraordinary Spiral from LL Pegasi
Explanation:
What created the strange spiral structure on the left?
No one is sure, although it is likely related to a star in a
binary star system entering the
planetary nebula phase,
when its outer atmosphere is ejected.
The
huge
spiral spans about a third of a
light year across
and, winding four or five complete turns, has a regularity that is without precedent.
Given the expansion rate of the
spiral gas, a new layer must appear
about every 800 years, a close match to the time it takes for the two stars to orbit
each other.
The star system that created it is most commonly known as LL Pegasi, but also AFGL
3068. The unusual structure itself has been cataloged as
IRAS 23166+1655.
The
above image was
taken in near-
infrared light by the
Hubble Space Telescope.
Why the
spiral glows is itself a mystery,
with a leading hypothesis being illumination by light reflected from nearby stars.
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.
