Extraolar Planets and Brown Dwarfs

One of the biggest challenges of contemporary Astronomy is to discover planets orbiting other stars, different than our sun, called “Extrasolar planets”. The discovery of an Extrasolar Planet habitable for humans will not impact only to science, but to whole humanity.

Extrasolar Planets

The first Exoplanet was discovered in 1995. Finding these objects is not an easy thing. How to find them if they don’t shine? Scientists use two main measurement techniques:

1. The "radial velocity method”, is the indirect and most successful way for detecting the presence of planets. These mechanisms also allow us to known their mass. If the star has a planet orbiting around it, the Gravity Effect will have small speed variations.

2. The "transit method" studies the variations in the brightness of a star when a planet passes in front of it (phenomena called Eclipse). With these data, the researchers can determine the size of the planet observed.

Achievements: CATA members have discovered, along with researchers from other countries, twenty Extrasolar Planets. An important number, because during the whole science history astronomers have found about 400 of these objects. 

Brown Dwarfs

Brown dwarfs are failed stars. Just at the beginning they shine regard the nuclear reactions generated inside of them, and at the same time that gives rise to their “fuel”. Then they stop having nuclear reactions, which is the basic feature in order to be a star.

Astronomers understand quite well the largest brown dwarfs (which are the size of the least massive stars). But that not happened with the smallest: about 13 times the size of Jupiter.

What can researchers do? Think that these small brown dwarfs are formed like the planets? The answer is at least complicated ... the origin of planets and stars are very different. But brown dwarfs are not stars (one step further of difficulty).

CATA‘s researchers work on these problems establishing a clear differentiation in the lower limit (from what size a brown dwarf is considered as itself). Also, they try to unravel the mysteries of these objects. For example, their internal structure.

How do they do? From ground-based telescopes in Chile, CATA‘s researchers look for brown dwarfs and try to characterize them through spectroscopic and satellite images (a kind of fingerprint that all the elements has). While more stars can be studied, the easier is to build a common pattern.

Like humans, stars are born in regions of galaxies than can be called “Stellar Nurseries”.

















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