About This Image
This image captures the irregular dwarf galaxy I Zwicky 18 and a companion galaxy to its upper right. The two galaxies are interacting, triggering star formation in I Zwicky 18.
Scientific Significance
I Zwicky 18 is a key nearby analog for chemically primitive galaxy evolution. It constrains star-formation behavior and metal retention in low-mass systems across long timescales.
Observation Details
Hubble deep imaging resolved faint red giant stars and bright young clusters in the same field, enabling robust reconstruction of mixed-age stellar populations.
Location in the Universe
Constellation
Ursa Major
Distance from Earth
59 million light-years
Fun Facts
- 1
I Zwicky 18 has one of the lowest heavy-element abundances in nearby galaxies.
- 2
Its bright blue knots are active starburst regions triggered by interaction.
- 3
Deep Hubble data detected older stars beneath the young burst population.
Image credit: NASA, ESA, Hubble Space Telescope
