Milky Way's Neighbor Is a Clean Freak

Galaxies are known to contain stars, planets gas and dust, but one particular nearby dwarf galaxy is notable for lacking the latter — it’s astonishingly dust-free.

IC 1613 is a well-known irregular dwarf galaxy in the constellation Cetus (The Sea Monster) and because of its tidy nature, astronomers have been able to observe its stars with striking precision. We now know that the diminutive galaxy is 2.3 million light-years away, placing it within the Local Group, our galactic neighborhood that is made up of over 50 galaxies.

Astronomers have been able to pinpoint IC 1613′s position by studying the Cepheid variable and RR Lyrae variable stars it contains. These variable stars pulse and the timing of these pulsations directly relate to their intrinsic brightness — astronomers can then use these stars as “standard candles”. The further away a star is, the dimmer it becomes (a logical conclusion), but these variables are known to have specific brightnesses depending on their measured pulse rates. Therefore, a relatively simple calculation can take their measured brightness to derive their distance.

Variable stars can be used to measure cosmic distances and in the case of IC 1613, this distance measurement is even more precise thanks to its dust-free nature.

This particular observation of IC 1613 was imaged by the powerful OmegaCAM, 256-million-pixel camera attached to the 2.6-meter VLT Survey Telescope at Paranal Observatory in Chile. The galaxy’s faint glow was first seen in 1906 by German astronomer Max Wolf, but IC 1613′s individual stars weren’t imaged until Walter Baade used the 2.5-meter telescope at the Mount Wilson Observatory in California in 1928.

Now, with the power of modern telescopes and imaging technology, IC 1613′s striking beauty — and freakish cleanliness — can be fully appreciated.

From Discovery News