Exoplanet Imager Begins Hunt for Alien Worlds

This infrared image shows the dust ring around the nearby star HR 4796A in the southern constellation of Centaurus.

Excerpt from news.discovery.com

By Ian

O’Neill

A new instrument attached to one of the most powerful telescopes

in the world has been switched on and acquired its ‘first light’ images

of alien star systems and Saturn’s moon Titan.

The Spectro-Polarimetric High-contrast Exoplanet REsearch (or

SPHIRES) instrument has been recently installed at the ESO’s Very Large

Telescope’s already impressive suite of sophisticated instrumentation. The VLT is located in the ultra-dry high-altitude climes of the Atacama Desert in Chile.




In the observation above, an ‘Eye of Sauron‘-like

dust ring surrounding the star HR 4796A in the southern constellation

of Centaurus, a testament to the sheer power of the multiple technique

SPHIRES will use to acquire precision views of directly-imaged

exoplanets.

The biggest problem with trying to directly image a world

orbiting close to its parent star is that of glare; stars are many

magnitudes brighter that the reflected light from its orbiting

exoplanet, so how the heck are you supposed to gain enough contrast

between the bright star and exoplanet to resolve the two? The SPHIRES

instrument is using a combination of three sophisticated techniques to

remove a star’s glare and zero-in on its exoplanetary targets.

The first technique, known as adaptive optics, is employed by

the VLT itself. By firing a laser into the Earth’s atmosphere during the

observation, a gauge on the turbulence in the upper atmospheric gases

can be measured and the effects of which can be removed from the

imagery. Any blurriness caused by our thick atmosphere can be adjusted

for.

Next up is a precision coronograph inside the instrument that

blocks the light from the target star. By doing this, any glare can be

removed and any exoplanet in orbit may be bright enough to spot.




But the third technique, which really teases out any exoplanet

signal, is the detection of different polarizations of light from the

star system. The polarization of infrared light being generated by the

star and the infrared glow from the exoplanet are very subtle. SPHIRES

can differentiate between the two, thereby further boosting the

observation’s contrast.

“SPHERE is a very complex instrument. Thanks to the hard work

of the many people who were involved in its design, construction and

installation it has already exceeded our expectations. Wonderful!” said

Jean-Luc Beuzit, of the Institut de Planétologie et d’Astrophysique de

Grenoble, France and Principal Investigator of SPHERE, in an ESO press

release.

The speed and sheer power of SPHIRES will be an obvious boon to

astronomers zooming in on distant exoplanets, aiding our understanding

of these strange new worlds.

Source Article from http://feedproxy.google.com/~r/AscensionEarth2012/~3/zIvS-TJqnUM/exoplanet-imager-begins-hunt-for-alien.html

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Exoplanet Imager Begins Hunt for Alien Worlds