The Arp 78 galaxy, also designated as NGC 772, is located in the constellation Aries. It is situated approximately 100 million light-years from the Milky Way and spans 200,000 light-years in diameter.
The galaxy features a prominent outer spiral arm characterized by dust lanes and clusters of young blue stars. Astronomers attribute the structure of this arm to gravitational tidal forces caused by interactions with a companion galaxy.
The companion galaxy, NGC 770, is a compact elliptical object positioned below the main spiral. Deep telescopic imaging reveals faint star streams surrounding the interaction site between the two galaxies.
