Imaginea Astronomica a Zilei

Descopera cosmosul! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

November 3, 1998
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Sextans A: A Seemingly Square Galaxy
Credit: S. D. Van Dyk (IPAC /Caltech) et al., KPNO 2.1-m Telescope, NOAO

Explicatie: (Edit) What's bothering local galaxy Sextans A? A small dwarf irregular galaxy spanning 5 thousand light years across, Sextans A is located only 5 million light-years away. Named for its home constellation of Sextans, the "diamond in the rough" structure relates to an ancient unknown event. 100 million years ago, something mysterious started a new wave of star formation in Sextans A's center. Massive short-lived stars exploded in supernovae that caused more star formation and yet more supernovae, ultimately resulting in an expanding shell. Today, young blue stars highlight areas and shell edges high in current star formation, a shell that from our perspective appears roughly square. In the above picture, a bright orange star in our own Milky Way Galaxy appears superposed in the foreground.

Imaginea de maine: Cosmology Solved?

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Autori & editori: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
Reprezentanti tehnici NASA: Jay Norris. Specific rights apply.
Un serviciu al: LHEA at NASA/ GSFC
&: Michigan Tech. U.