Astronomers start searching for "orphan stars" using upgraded telescope

Washington, May 20 : Astronomers from the Case Western Reserve University in the US have begin searching for the faint sea of orphan stars strewn throughout the nearby Virgo cluster of galaxies, using a newly upgraded telescope.

The telescope, at Kitt Peak National Observatory in Tucson, Arizona, has been upgraded by the installation of a new camera system on it.

Case Western Reserve astronomer Paul Harding led the design and installation of the new camera system.

A new charge coupled device (CCD) - a larger and more sensitive version of the imaging technology found in everyday digital cameras - will enable the astronomers to determine the ages of these stars and unravel the secrets of their origins.

This faint orphan starlight, dubbed "intracluster light," is formed when galaxies collide with one another inside titanic clusters of galaxies.

During these collisions, stars are ripped away from their parent galaxies and strewn throughout the cluster by the gravitational forces at work.

Originally discovered in the Virgo cluster three years ago by Case astronomer Chris Mihos and his collaborators, this intracluster light holds the key to understanding how galaxy clusters form and evolve.

According to Mihos and Harding, the primary reason for upgrading the telescope's camera is to determine the color of these stars.

"Typically younger stars are bluer," said Harding. "So, if we can measure the color of the intracluster light, we can learn about its age," he added.

Younger ages for the stars would suggest that the Virgo cluster formed relatively recently, over the past few billion years.

But because the stars are very faint in the blue, to measure the stellar colors the existing camera needed to be upgraded to be image a wider portion of the sky with even greater sensitivity.

The telescope's upgraded camera images an area of the sky 1.5 degrees on a side - twice as big as the old camera, and enough to fit nine full moons in the field of view.

"By imaging twice as much sky, we can collect twice as much light at once, and that lets us detect this faint starlight even in the blue where it is extremely faint," said Mihos.

ANI