Arp 78: A Peculiar Spiral Galaxy in Aries

• The peculiar spiral galaxy Arp 78 (NGC 772) has been captured in a detailed cosmic portrait.
• Located in the constellation Aries, the galaxy resides about 100 million light-years away from Earth.

Physical Characteristics

• The galaxy spans approximately 200,000 light-years in diameter.
• It features an overdeveloped, prominent outer spiral arm filled with dusty lanes and young blue star clusters.

Galactic Interaction

• The enlarged spiral arm is driven by galactic-scale gravitational tides.
• Observations suggest these tides result from interactions with a compact companion galaxy, NGC 770, positioned directly below the larger spiral.
• Deep telescope exposures reveal faint star streams, highlighting the gravitational relationship between the two galaxies.