Mapping our galaxy

Telescope in Chile continues to lift dust shroud off galaxy

Massive star nursery in the Lobster Nebula seen with unreal clarity as the ESO’s VISTA telescope wipes the dust away from Milky Way imaging.

Tuesday, March 05, 2013 Category: Education
Swirling tendrils of gas reach out from the Lobster Nebula. Photo courtesy of ESO. Swirling tendrils of gas reach out from the Lobster Nebula. Photo courtesy of ESO.

 

From its home in the arid climes of northern Chile’s Atacama Desert, the Visible and Infrared Survey Telescope for Astronomy (VISTA) produces the most detailed imagery of our galaxy ever, and its latest effort has provided yet more data for astronomers in pursuit of a comprehensive understanding of star formation.

Located 8,000 light years from earth in the Scorpius constellation, the enormous stellar nursery NGC 6357, or the Lobster Nebula, has long intrigued astronomers searching for clues into how stars come to be. Yet under the view of conventional visible light telescopes, much of the nebula has remained hidden by swathes of dust.

Using VISTA’s infrared technology, these clouds fall away, as infrared radiation penetrates dust interference, providing astronomers with far more intricate viewing. The contrast is shown well by an image taken from a 1.5 meter visible light telescope at La Silla Observatory in Chile. The nebula get its nickname from the red hue seen in the image, whereas through VISTA the nebula appears largely purple.

Operated by the European Southern Observatory (ESO), VISTA is the largest survey telescope ever built, and is currently being used in an ambitious project to map the center of our galaxy, known as the Galactic Bulge, and explain how it was formed. The project has produced the largest image of the Milky Way ever taken, registering an astonishing nine billion pixels - a zoomable version of the image can be seen here.

“By observing in detail the myriads of stars surrounding the centre of the Milky Way we can learn a lot more about the formation and evolution of not only our galaxy, but also spiral galaxies in general,” said Roberto Saito, astronomer at Pontificia Universidad Católica de Chile and lead author on the project.

Better viewing of the Lobster Nebula has led to some revisions. One of the nebula’s brightest young stars, Pismis 24-1, was thought to be the most massive star known — until it was found to actually be made up of at least three huge bright stars, each with a mass of under 100 times that of our Sun. Even so, these stars remain among the largest in our galaxy.

Due to its almost non-existent humidity and clear skies, the Atacama Desert is the planet’s premier location for astronomy. Chile is home to almost half the world’s telescope infrastructure, and this is set to increase to over two thirds by 2018.

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