Peruvian astronomers Jorge Melendez of the Australian National University, and Ivan Ramirez of the University of Texas at Austin, USA, has found a "solar twin" the best at this time. The discovery was achieved using a 2.7-meter telescope, Harlan J. Smith at McDonald Observatory. Their findings showed that the chemical composition of the Sun was not unique as previously thought.
The star, HIP 56948, is more similar to the sun than any has ever known. Located 200 light-years so far in the constellation Draco, the star of about a billion years younger than the Sun.
Previously, only three twin sun is known, each is 18 Scorpii, HD 98618, and HIP 100963. However, although in some ways similar to the sun, the three stars has fundamental differences in content far exceeds it lithium lithium content in the sun. Lithium content of the very few in the Sun could make the astronomers assumed that the Sun is a very unique star among other stars.
The discovery of new solar twin assumptions that break. HIP 56948 lithium known to have the same content with the sun low. This study also reveals the other twin of the Sun, HIP 73815, which also has the same lithium content is low.
Questions about the uniqueness of the sun associated with what is known as the "principle antropik" (anthropic principle), the question of whether there is something special to the Sun that enables living organisms evolved in our solar system. This finding does not fully answer that question, but it only shows that the uniqueness is clearly not on their chemical composition.
Melendez and Ramirez findings support the opposite of antropik principle, called the outlook "Copernician", that is the possible existence of living organisms can be found anywhere in the universe. Both suggest that stars like HIP 56948 could be a good target for the researchers at the SETI program (Search for Extra-Terresterial Intelligence).
The star has been studied by Planet Search Program at the McDonald Observatory, led by astronomer Bill Cochran of the University of Texas. Cochran and his team found that, like our sun, HIP 56948 has no planetary class "hot Jupiter" - a large mass planets, has a short orbital period, and the circle around its parent star in a very close range. This type of known planets is very common. Up to now been found more than 200 stars that have one or more hot Jupiter-class planet orbiting.
Search "solar twin" was considered important because astronomers use the Sun as a benchmark in many studies. However, they can not learn the Sun in the same way as they study the distant stars, because the distance is too close, and the appearance of too light.
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