Barred Spiral Galaxy NGC 4490, Irregular Galaxy NGC 4485, aka Arp 269

& Supernova 2008ax

Interacting Galaxies NGC 4490 and NGC 4485

A 15:5:5:10 minute LRGB exposure with an STL-1301E CCD camera thru Kopernik's 20-inch F/8.1 Ritchey Chretien Cassegrain telescope. The field of view is about 13x16 arc minutes, with North at the top.
Time: 4:30 UT, March 30th, 2008.

Supernova 2008ax:

Discovered March 3rd, 2008, independantly by the Lick Observatory Supernova Search (USA), Koichi Itagaki (Japan).

Follow this Link to a NASA Web site on supernovas. It has a very nice animation and a description of what these objects are.

Arp 269:

Dr. Halton C. Arp included this pair of interacting (colliding?) galaxies in his "Atlas of Peculiar Galaxies" as entry number 269. Both galaxies in the group show signs of collision and an unusually high rate of star formation. The pair is located in the Constellation of Canes Venatici. A rough distance estimate is 35 million light years.

Barred Spiral Galaxy NGC 4490:

This peculiar galaxy is partially resolved into stars and has irregular dark markings and bright H-II regions. While it shows characteristics of a Barred Spiral Galaxy, it is distorted by its interaction with NGC 4485. There is a connecting streamer of stars, gas, and dust running between the two galaxies. NGC 4490 is the host of Supernova 2008ax and was previously the host of Supernova 1982F. The length of the galaxy is estimated to be 65,000 light years.

Irregular Galaxy NGC 4485:

This small Irregular Galaxy is tidally interacting with NGC 4490. It appears that the tidal interaction triggered a recent burst of star formation in both of these galaxies.

  • NGC 4490
  • Magnitude: 9.8
  • Constellation: Canes Venatici
  • RA: 12h 30m 36.6s
  • Dec: +41° 38' 23" Epoch 2000
  • Size (mins): 6.3' x 3.1'
  • Classification: SB(s)d pec, Barred Spiral, S-shaped, peculiar.

  • NGC 4485
  • Magnitude: 12.5
  • Constellation: Canes Venatici
  • RA: 12h 30m 31.6s
  • Dec: +41° 42' 01" Epoch 2000
  • Size (mins): 2.3' x 1.6'
  • Classification: IB(s)m pec HII, Irregular, Barred & S-Shaped, peculiar, very high star formation rate.

    George Normandin, KAS

    March 30th, 2008