U.S. scientists have discovered a new class of planets whose mass is greater than the mass of the Earth is about 15-20 times and is approximately equal to the mass of Neptune. Almost all previously discovered outside the solar system before the planets have masses of 300 or more times the mass of Earth. Such giant planets may only be gas giants.
The first exoplanet with a smaller size has been found recently a group of researchers from Portugal. Planet orbiting the star Mu Altar, which is 50 light years from our solar system, about 14 times the mass of Earth and is comparable in mass to Uranus. As the planet is very close to its star, the researchers suggest that it has a solid surface. Gas planet in this case would be unstable and would simply evaporate, researchers believe. However, accurate data about the composition ekzoplanet currently generally are not available, as they are registered on indirect indicators such as weak vibrations star field influence of the gravitational field of the planet.
It thus were discovered two relatively small exoplanets, according to Reuters. First similar to the planet Neptune was discovered by Paul Butler and Geoffrey Marcy of the University of California, the star Gliese 436 in the constellation Leo, and is located about 30 light-years from Earth. The second planet found by Barbara McArthur of the University of Texas and is the star 55 Cancri is 40 light years from Earth. Both planets, as well as Planet Mu at the Altar are very close to their stars. Their revolution is only a few Earth days. Therefore, it is possible that they also have a solid surface, or at least a solid core around which is a kind of cocoon of gas. However, the probability that the new planets are fully gas, can not be discounted.
Finally, the nature of these planets will be clear after the scientists will be in the hands of the tools to observe exoplanets directly, not indirectly. However, the detection of planets with masses close to the mass of Uranus and Neptune, suggests that the more compact the planet like the Earth, Venus or Mars are quite common and beyond the solar system. The number of giant exoplanets have long exceeded one hundred.
Battery News, 02.09.2004 11:12