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Астронет: Астрономическая картинка дня Мессье 20 и 21 http://variable-stars.ru/db/msg/1684238/eng |
Credit & Copyright: Emanuele Petrilli
Explanation:
The beautiful Trifid Nebula,
also known as Messier 20, is easy
to
find with a small telescope in the nebula rich constellation
Sagittarius.
About 5,000 light-years away, the colorful study in
cosmic contrasts shares
this well-composed, nearly 1 degree wide field with
open star cluster
Messier 21
(right).
Trisected by dust lanes
the Trifid itself is about 40 light-years across and
a mere 300,000 years old.
That makes it one of the
youngest star
forming
regions in our sky,
with newborn and embryonic stars embedded in its
natal dust and gas clouds.
Estimates of the distance to open star cluster M21 are similar to M20's,
but though they share this gorgeous telescopic skyscape
there is no apparent connection between the two.
In fact, M21's stars are much older, about 8 million
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.