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In the Elqui Valley

Chilean observatory gets new images of galaxy near our own

As part of Project Araucaría, scientists at La Silla observatory will use images of galaxy NGC 247 to suggest changes to measuring inter-galactic distances based on pulsating stars.

Friday, March 04, 2011  
One of three powerful telescopes in Chile operated by the European Southern Observatory (ESO). One of three powerful telescopes in Chile operated by the European Southern Observatory (ESO).

After years of gathering photographic data though red, yellow, green, blue and hydrogen filters, a new image has been generated at the La Silla astronomical observatory in northern Chile’s Elqui Valley that depicts the galaxy NGC 247 with unprecedented clarity. The new image of the galaxy, one of the closest known spiral galaxies to our own Milky Way, shows brilliant pink clouds of hydrogen, an indication of stars being born within.
 
Part of the “Sculptor Group,” an agglomeration of galaxies located relatively near our own, NGC 247 is currently the focus of a study that aims to reevaluate the methods for measuring the distance of a type of variable star called a Cepheid. The astronomers behind the study, called Project Araucaría for the Chilean national tree, believe that NGC 247 is in fact at least 1 million light years closer to earth that previously believed. This would bring the galaxy to within 11 million light years of our own.
 
The period of pulsation for cepheids, extremely bright stars typically between four and 20 times larger than the sun, is currently used with a simple mathematical formula to determine the distance between that cepheids galaxy and our own. While this method has been in common practice for some time, certain variables have meant that the formula remains provisional and open to error.
 
Among the known variables are the chemical composition of different individual stars, which may affect luminosity and period. Another key variable, and one of particular interest for Project Araucaría, is the possibility that light from the pulsating stars may be absorbed by dust particles, thus diminishing its luminosity and increasing estimates of distance.
 
One of three powerful telescopes in Chile operated by the European Southern Observatory (ESO), La Silla is an epicenter for astronomy in Chile, taking advantage of the clear skies of the Elqui Valley near La Serena to capture images of ‘galactic cannibalism’ and extragalactic planets. The new image of galaxy NGC 247 is just the most recent in a long line of astounding images captured at this state of the art research center, just ours inland from La Serena.