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Астронет: Астрономическая картинка дня Планетарная туманность Эйбелл 7 http://www.variable-stars.ru/db/msg/1952928/eng |
Credit & Copyright: Vikas Chander
Explanation:
Very faint planetary nebula Abell 7 is about 1,800 light-years distant.
It lies just south of Orion in planet Earth's skies toward the constellation
Lepus, The
Hare.
Surrounded by Milky Way stars and near the line-of-sight to
distant background galaxies its
generally
simple spherical shape, about 8 light-years in diameter, is revealed in
this deep telescopic image.
Within the cosmic cloud are beautiful and complex structures though,
enhanced by the use of long exposures and
narrowband filters
that capture emission from hydrogen, sulfur, and oxygen atoms.
Otherwise Abell 7 would be much
too faint to be appreciated by eye.
A planetary nebula
represents a very brief final phase
in stellar evolution that our own Sun will experience 5 billion
years hence,
as the nebula's central, once sun-like star shrugs off its outer layers.
Abell 7 itself is estimated to be 20,000 years old.
But its central star, seen here as a
fading
white dwarf,
is some 10 billion years old.
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.