Researchers develop ‘astro-comb’ to locate earth-like planets

May 8th, 2009 - 5:10 pm ICT by IANS  

Washington, May 8 (IANS) The ability to detect presence of extrasolar planets orbiting distant stars has got better with researchers at the Harvard-Smithsonian Centre for Astrophysics creating an “astro-comb” to detect lighter planets, more like the Earth, around distant stars.
In most cases, extrasolar planets can’t be seen directly - the glare of the nearby star is too great - but their influence can be discerned through spectroscopy, which analyses the kind of light emanating from the star.

Not only does this “astro-comb” spectroscopy reveal the identity of the atoms in the star (each element emits light in a certain way), it can also tell researchers how fast the star is moving away or towards the Earth.

This process is used to judge the speed of automobiles, storm systems, fast balls, and stars. How can it be used to deduce the presence of a planet?

Though the planet might weigh millions of times less than the star, the star will be jerked around a tiny amount owing to the gravity interaction between star and planet.

This motion causes the star to move toward or away from Earth slightly in a way that depends on the planet’s mass and its nearness to the star, said a Harvard-Smithsonian release.

The better the spectroscopy used in this whole process, the better will be the identification of the planet in the first place and the better will be the determination of planetary properties.

Right now standard spectroscopy techniques can determine star movements to within a few metres per second. In tests, the Harvard researchers are now able to calculate star velocity shifts of less than this speed, allowing them to more accurately pinpoint the planet’s location.

The Harvard group will present their findings at the 2009 Conference on Lasers and Electro Optics/International Quantum Electronics Conference (CLEO/IQEC), from May 31 to June 5 at the Baltimore Convention Centre.

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