Ancient dwarf galaxy discovered in our neighborhood

The Hubble Space Telescope has identified a new dwarf galaxy near our Local Group, about two megaparsecs (or about 6.9 million light-years) away from the Earth. Unlike our own galaxy, the dwarf—known as KKs 3—is a spheroid and has no spiral arms. While the object has been detected in previous sky surveys, it has now been conclusively identified as a spheroidal dwarf galaxy.

The discovery is important for cosmological models involving dwarfs. Dwarfs of any kind seem to be present in much lower numbers than expected. Thirty spheroidal dwarfs have been discovered near the Local Group in the past decade, but it’s not known how many there are in total—finding a definitive number is essential for creating more detailed models of galaxy formation and evolution.

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The galaxy’s stars are very ancient. It contains plenty of red giants—inflated stars close to the end of their lives—a population that our Sun will one day join. The galaxy is also no longer producing new stars—a star hasn’t been born in KKs 3 in the past billion years. That's because the galaxy itself is very old, estimated to be over twelve billion years old. Thus, it provides astronomers with a fascinating glimpse into the very early Universe.