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Sunday, June 17, 2012

The primary survey of stars and the finding of other 'Earths', amazing closer


The primary survey of stars close to the Sun with Earth-like planets are faster to creature a actuality thanks to the spectrometer calibration technique, a technology used to calculate the speed of a star and make measurements with precision and accuracy "unprecedented." This has been noted scientists of the Max Planck, the European Southern Observatory, who have tried this technique to trace the orbit of an exoplanet discovered and which revolve around the star HD75289 and the results published in Nature.
This team of researchers has shown that the spectrometer calibration technique known as "laser frequency comb 'measures wavelengths radiating celestial objects with great precision, said today the National Research Council (CSIC) of Spain in a press release. To measure the velocity of a star or find planets around other stars the Astronomers use spectrometers. These instruments scatter light which reaches the earth from celestial objects, decomposing at wavelengths, frequencies or colors. A spectrometer must therefore be calibrated with a high accuracy using a technology, in this case the laser frequency comb that helps measure the wavelengths of the most accurate and stable as possible. According to the study, the technique, which earned physicists Theodor Hänsch and John Hall the Nobel Prize for Physics in 2005, assumes that the accuracy achieved with the same astronomical instruments is at least four times better. The secret of this improvement is in a laser system that generates a large set of light pulses with a frequency separation very close and very well defined. "The goal of our research was to demonstrate that it is feasible to make more accurate measurements of the velocity curve of a star, HD75289, we already knew that contained at least one planet, "explained CSIC researcher at the IAC Rafael Rebolo. In view, this technique "opens the way for the systematic search for Earth-like planets in the closest stars to the Sun." There are two important advantages of the new technique, according to Rebolo: "The first is that it provides a high density of frequency reference on the detector of the telescope, allowing better calibrate the frequencies of light we receive, and the other advantage is that the system is very stable, does not change over time. " Thanks to the comb of frequencies, scientists are able to measure more accurately the effect exerted on a planet orbiting the star, seen through subtle movements or small changes in the spectrum. These movements are measured by reference to a light source to be extremely stable. The technique offers a light source much more stable than any available today. "The technique will be a leap in the precision of spectrographs opening new options for astronomical research. The measurement of velocities of stars can be made ​​with accuracies few centimeters per second, "said Rebolo. In the long run, when the next generation of optical telescopes available land, this technique will become a "vital instrument" to measure the expansion rate of the universe, scientists say.

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