Hubble Telescope Discovers Dwarf Galaxy Located Only 30 Million Light-Years Away

| February 1, 2019 | Astronomy | No Comments

MessageToEagle.com – Astronomers using the NASA/ESA Hubble Space Telescope discovered a dwarf galaxy in our cosmic backyard, only 30 million light-years away.

An international team of astronomers recently used the NASA/ESA Hubble Space Telescope to study white dwarf stars within the globular cluster NGC 6752. The aim of their observations was to use these stars to measure the age of the globular cluster, but in the process they made an unexpected discovery.

This image, taken with Hubble’s Advanced Camera for Surveys shows a part the globular cluster NGC 6752. Behind the bright stars of the cluster a denser collection of faint stars is visible — a previously unknown dwarf spheroidal galaxy. This galaxy, nicknamed Bedin 1, is about 30 million light-years from Earth. Credit: ESA/Hubble, NASA, Bedin et al.
This image, taken with Hubble’s Advanced Camera for Surveys shows a part the globular cluster NGC 6752. Behind the bright stars of the cluster a denser collection of faint stars is visible — a previously unknown dwarf spheroidal galaxy. This galaxy, nicknamed Bedin 1, is about 30 million light-years from Earth. Credit: ESA/Hubble, NASA, Bedin et al.

After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster — which is part of the Milky Way — but rather they are millions of light-years more distant.

The galaxy nicknamed Bedin 1 is a modestly sized, elongated galaxy. It measures only around 3000 light-years at its greatest extent — a fraction of the size of the Milky Way. Not only is it tiny, but it is also incredibly faint. These properties led astronomers to classify it as a dwarf spheroidal galaxy.

Dwarf spheroidal galaxies are defined by their small size, low-luminosity, lack of dust and old stellar populations. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.

While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Not only is it one of just a few dwarf spheroidals that have a well established distance but it is also extremely isolated. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744. This makes it possibly the most isolated small dwarf galaxy discovered to date.

The galaxy is around 13 billion years old — nearly as old as the Universe itself. Very few Hubble images allow such faint objects to be seen, and they cover only a small area of the sky. Future telescopes with a large field of view, such as the WFIRST telescope, will help us to view much more.

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