Q1107153

interacting galaxy

Key facts

Constellation: Ursa Major
Right ascension: 11 51 06.863
Declination: +55 ° 04 ′ 43.38 ″
Heliocentric radial velocity: 5896 km/s
Distance: 277.9 Mly (85.19 Mpc )
Absolute magnitude v: − 22.09
Type: (R')SA0/a(s) pec
Size: 180,200 ly (55,240 pc )
Apparent size v: 2.1 ′ × 1.3 ′

via Wikipedia infobox

Wikidata facts

Distance from Earth: 85.19
Image: NGC3921-HST-814-R814GB555.jpg

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catalog code: Gaia DR2 841656192350581376
Commons category: NGC 3921
time of discovery or invention: 1789-04-14
apparent magnitude: 9.814
redshift: 0.019680
right ascension: 177.77864420591290
declination: 55.07872009362870
radial velocity: 5842
galaxy morphological type: 0

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Article

NGC 3921 is an interacting galaxy in the northern constellation of Ursa Major. Estimates using redshift put it at about 59 million light years (18 megaparsecs) from Earth. It was discovered on 14 April 1789 by William Herschel, and was described as "pretty faint, small, round" by John Louis Emil Dreyer, the compiler of the New General Catalogue.

NGC 3921 is the remnant of a galaxy merger. The two progenitor galaxies are thought to have been disk galaxies that collided about 700 million years ago. The image shows noticeable star formation and structures like loops, indicative of galaxies interacting. Because of this, NGC 3921 was included in Halton Arp's Atlas of Peculiar Galaxies under the designation Arp 224.