NGC 3786 and NGC 3788 (aka Arp 294)
An Interacting pair of Galaxies

Supernova 2004bd:

• Discovered: March 22, 2004, by Mark Armstrong (UK);
• Magnitude 16.5 in the Kopernik image.
• Type: Ia found at maximum brightness

NGC 3786 and NGC 3788, are a pair of closely interacting spiral galaxies that appear to be in contract. Both galaxies appear to be highly disturbed. NGC 3786 was the host of the unusual Type Ic Supernova 1999 bu.

Temple discovered the pair in the 19th century. He reported a third nebula (NGC 3793), but there is only a faint background galaxy in the area, and from his notes it is very likely that he actually saw a close group of three stars rather than another galaxy. Thus modern astronomers consider NGC 3793 as 'non-existent'.

One current theory would suggest that these two are in the process of merging into a single elliptical galaxy. Some astronomers predict that this is the fate that awaits the Milky Way and spiral galaxy M-31 in about 5 billion years.

This pair is included in Arp’s catalog of unusual galaxies as "ARP 294". It is in Arp's class "double galaxies with long filaments". Using the red shift data from the “NASA Extra-galactic Data Base(NED)”, (and a Hubble Constant of 62 Km per sec., per Megaparsec), one can calculate a rough distance for the galaxy pair Arp 294 of 141 million light years.

NGC 3786 (ARP 294) Magnitude: 13.2 Constellation: Ursa Major RA: 11h 39m 42.4s Dec: +31° 54' 35" Epoch 2000 Size (mins): 2.1' x 1.3' Classification: SAB(rs)a pec        Mixed Barred Non-barred Spiral, mixed Inner Ring S-shaped, peculiar Deep Sky Field Guide:        "Very bright, diffuse nucleus, bright lens 1.0' x 0.55' with dark lane."

NGC 3788 (ARP 294) Magnitude: 13.5 Constellation: Ursa Major RA: 11h 39m 44.0s Dec: +31° 55' 58" Epoch 2000 Size (mins): 2.1' x 0.7' Classification: SAB(rs)ab pec        Mixed Barred Non-barred Spiral, mixed Inner Ring S-shaped, peculiar Deep Sky Field Guide:     "Extremely bright nucleus and inner lens, very bright lens 0.9' x 0.2', massive, very bright arms."

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George Normandin, KAS

April 23rd, 2004