May 29 (Xinhuanet) — A leading team of planet-seekers has announced the discovery of 28 new planets outside solar system, increasing the number of known exoplanets to 236, at the annual meeting of American Astronomical Society in Honolulu, Monday.
Jason Wright of the University of California, a member of the team, said at the meeting: “Taken together, in the last year our teams have increased the number of known planets by 12 percent and shown that at least 30 percent of stars known to host planets have more than one object orbiting.”
The planets are among 37 new objects spotted within the past year. Seven of the objects are failed stars called brown dwarfs, with masses that dwarf the largest, Jupiter-sized planets but too small to sustain the nuclear reactions necessary for stellar ignition.
At least four of the newly spotted planets belong to multiple-planet systems, supporting the idea that at least 30 percent of all planet-parent stars have more than one planetary companion. Since smaller planets and those outside our solar system are trickier to detect,
“We are beginning to see that our home is not a rarity in the universe,” said Geoffrey Marcy, a professor of astronomy at the University of California Berkeley.
“We are easily able to detect giant planets like Jupiter and Saturn around other stars. Most orbit far from the star like our own Jupiter and Saturn orbit from the sun.” Marcy added.
Among the 28 new planets, a Neptune-like planet orbiting the star Gliese 436 is found covered with water — albeit rock-hard, hot water in a most un-earthlike chemical state because of the intense pressures on the planet.
Wright said that this is the first planet outside the solar system for which astronomers could infer the presence of water with near certainty, but he cast doubt on the idea that there is life there. “These planets, like most of the giant planets in our solar system, will probably have no solid surface.”