This Hubble image shows IC 3430, a dwarf elliptical galaxy in the constellation Virgo. Despite its lack of distinctive structural features, IC 3430 shows signs of recent star formation at its core, an unusual feature for its type of galaxy, attributed to the effects of shock pressure in the Virgo cluster. Credit: ESA/Hubble and NASA, M. Sun

IC 3430, a dwarf elliptical galaxy in the Virgo Cluster, stands out because of its core of hot blue stars, indicating recent star formation, a rare feature for its type, likely caused by its motion through the cluster.

This majestic Hubble Space Telescope The image reveals the subtle glow of the galaxy called IC 3430, located 45 million light-years from Earth in the constellation Virgo. It is part of the Virgo Cluster, a rich collection of large and small galaxies, many of which are very similar in type to this tiny galaxy.

IC 3430 is a dwarf galaxy, a fact well reflected in this Hubble image, but it is more accurately known as a dwarf elliptical galaxy or dE galaxy. Like its larger cousins, this galaxy has a smooth, oval shape that lacks recognizable features such as arms or bars, and is devoid of gas to form many new stars. Interestingly, IC 3430 features a core of massive, hot blue stars, a rare sight in elliptical galaxies that indicates recent star-forming activity. The pressure of the galaxy pushing through the gas within the Virgo Cluster is thought to have ignited the remaining gas in IC 3430’s core to form some new stars.

Full, uncropped Hubble image of IC 3430. Credit: ESA/Hubble and NASA, M. Sun

Dwarf galaxies are actually galaxies with only a few stars, usually less than a billion, but that is often enough for them to reproduce in miniature the same shapes as larger galaxies. There are elliptical dwarf galaxies like IC 3430, irregular dwarf galaxies, spheroidal dwarf galaxies and even spiral dwarf galaxies. The so-called Magellanic spiral is also a distinct type of dwarf galaxy, the best example being the well-known dwarf galaxies known as the Magellanic Clouds.