This
Astrobin Debut Object, also known as the IC 1892 chain, is a galaxy chain located in the constellation of Eridanus at a declination of -23 degrees. In his
Arp catalog, Dr. Arp classified this object into the category of Chains of Galaxies.
The criteria for what makes up a galaxy chain is subjective. Dr. Arp considered a galaxy chain to be a “group of four or more galaxies which stand out in brightness and closeness as a group, and which are, at the same time, noticeably aligned.” He had a preference for those chains which shown some visible disturbance, thereby confirming that they are likely related and not just visually aligned.
The 3 bright galaxies on the left side of the image (NGC 1228, 1229 & 1230 respectively) are all about 0.5 billion light years away. The largest of these, NGC 1228, is similar in size to our Milky Way, at 120,000 light years in diameter. Of these 3 galaxies, the 2 on the left appear disturbed.
The large galaxy on the right (IC 1892) is much closer at 120 million light years. It is also smaller at 60,000 light years in diameter. The “companion” to its left is much further away, similar to the other 3 left galaxies at 0.5 billion light years.
The cause of the disturbance to IC 1892 is not clear. The disk of IC 1892 is messy, especially on the lower right side. That bright blue region could be the remnants of a dwarf galaxy which is now merging with IC 1892.
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