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The Hubble\u00a0Picture of the Week\u00a0this week reveals the subtle glow of the\u00a0galaxy\u00a0named IC 3430, located 45 million light-years from Earth in the constellation Virgo. It is part of the Virgo cluster, a rich collection of galaxies both large and small, many of which are very similar in type to this diminutive galaxy.<\/p>\n
IC 3430 is a\u00a0dwarf galaxy, a fact well reflected by this view from Hubble, but it is more precisely known as a dwarf\u00a0elliptical\u00a0or dE galaxy. Like its larger cousins, this galaxy has a smooth, oval shape lacking any recognisable features like arms or bars, and it is bereft of gas to form very many new stars. Interestingly, IC 3430 does feature a core of hot, massive blue stars, an uncommon sight in elliptical galaxies that indicates recent star-forming activity. It\u2019s believed that\u00a0ram pressure\u00a0from the galaxy ploughing through gas within the Virgo cluster has ignited what gas does remain in IC 3430\u2019s core to form some new stars.<\/p>\n
Dwarf galaxies are really just galaxies with not many stars, usually fewer than a billion, but that is often enough for them to reproduce in miniature the same forms as larger galaxies. There are dwarf elliptical galaxies like IC 3430, dwarf irregular galaxies,\u00a0dwarf spheroidal galaxies\u00a0and even\u00a0dwarf spiral galaxies! The so-called\u00a0Magellanic spiral\u00a0is a distinct type of dwarf galaxy, too, the best example being the well-known dwarf galaxies that are the Magellanic Clouds.<\/p>\n
[Image Description:<\/i>\u00a0A relatively small, oval-shaped galaxy, tilted diagonally. It glows brightly at the centre and dims gradually to its edge. At the centre it is crossed by some wisps of dark dust, and a few small, blue, glowing spots are visible, where stars are forming. The galaxy is on a dark background in which many background galaxies and foreground stars can be seen.]<\/p>\n<\/p><\/div>\n<\/p><\/div>\n