This
Astrobin Debut Object, also known as VV 790b and Zw II 28, is a
collisional ring galaxy located 0.4 billion light years away in the constellation of Orion at a declination of +4 degrees. It is a magnitude 16 galaxy and spans 15 arc-seconds in our apparent view, about the same current size to our apparent view as our planet Venus. At a distance of 0.4 billion light years, this corresponds to a diameter of 30,000 light years.
Collisional ring galaxies occur when a larger galaxy (typically 30,000 to 50,000 light years in diameter) is impacted head-on along its polar axis by a smaller dwarf galaxy (typically 5,000 to 10,000 light years in diameter). The collision creates an expanding density wave of star formation in the larger galaxy, leading to the formation of a hole in the larger galaxy which usually develops into a ring. Surprisingly, the small galaxy often remains relatively intact.
The mouseover shows PGC 16572 and the suspected intruder. The intruder seems to be a likely candidate but no distance information is available to confirm that it is at the same distance as PGC 16572. If it is at the same distance, it is a blue dwarf galaxy about 10,000 light years in diameter.
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