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Астронет: Астрономическая картинка дня Кольца и перемычка в спиральной галактике NGC 1398 http://variable-stars.ru/db/msg/1904934/eng |
Credit & Copyright: Mark Hanson;
Data: Mike Selby
Explanation:
Why do some spiral galaxies have a ring around the center?
Spiral galaxy
NGC 1398 not only has a
ring of pearly stars, gas and
dust around its center, but a
bar of stars and gas across its center,
and spiral arms that appear like ribbons farther out.
The featured deep image from
Observatorio El Sauce in
Chile
shows the
grand spiral galaxy in impressive detail.
NGC 1398 lies about 65 million
light years distant, meaning the light we see today left this galaxy when
dinosaurs were disappearing from the
Earth.
The photogenic galaxy is visible with
a small telescope toward the constellation of the Furnace
(Fornax).
The ring near the center is likely an expanding
density wave of star
formation, caused either by a
gravitational encounter with another galaxy,
or by the galaxy's own
gravitational asymmetries.
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.