Hubble captures rare "tadpole" galaxy during a dramatic bout of star creation
The Hubble Space Telescope has captured amaelstrom of star creation taking place in a nearby "tadpole"galaxy known as Kiso 5639. The activity was unexpected, as the galaxyis thought to be passing through a desert-like region of space devoidof the vital materials needed for the creation of new stars.
The discovery of a specimen such as Kiso 5639 amere 82 million light-years away amongst the largely spiral andelliptical galaxies that make up the Milky Way's neighbours is a rarefind indeed. Described as "tadpole galaxies" due to their brightheads and extended tails, this family of galaxies is thought to havebeen much more common in the early universe, and appear often inHubble's Ultra-Deep Field images.
Out of a sample of 10,000 galaxies in the localuniverse, there is expected to be a mere 20 tadpoles in our littlecorner of the universe. Due to the relative lack of primordial gas inthe region, the galaxy has suffered a stunted evolution, with themajority its the stars dating back to the time at which the galaxyfirst formed.
However, upon analysis of the Hubble data,astronomers discovered a flurry of star formation taking place in thehead of the tadpole. Several dozen youthful star clusters weredetected within the 2,700 light-year wide expanse, all of which wereestimated to be less than 1 million years old. This makes them merebabies compared to clusters permeating the rest of the galaxy, manyof which are billions of years old.
The clusters that house the younger generation ofstars are thought to be far larger than their geriatric counterparts.It is estimated that the newly created stellar bodies boast acumulative mass the equivilent to 10,000 Suns. Researchers attributethe unexpected bout of star formation to an influx of interstellarmaterial, which is being drawn into the galaxy as it passes through arare filament of primordial gas punctuating the otherwise barrenexpanse.
By using special filters to split the light downinto its component wavelengths, astronomers noted a distinct lack ofheavy elements in the gas that makes up the head region of Kiso 5639.This is due to the fact that the gas has yet to be subjected to thedramatic lifecycle of stars, which will see the material transformedinto heavier elements in the hearts of the new generation of starsthrough stellar fusion, and subsequently distributed through violentsupernova explosions.
Whilst star birth is illuminating the head of thegalaxy, the dramatic deaths of a number of older cosmic giants arealso leaving their mark. The new release reveals that the head ofKiso 5639 is riddled with holes, created as the forces released bycataclysmic supernovae explosions from the last generation of starscarve out vast cavities in the surrounding clouds of dust and gas.
In the same way that the Milky Way rotates as itlumbers through space, Kiso 5639 is also constantly on the move. Thespinning motion is likely to bring more of the tadpole galaxy intocontact with the material filament, which will lead to star formationspreading beyond the head to other regions of the galaxy.