A new planet
taken from:http://www.space.com/scienceastronomy/060125_smallest_planet.html
Astronomers announced today the discovery of what is possibly the smallest planet known outside our solar system orbiting a normal star.
Its orbit is farther from its host star than Earth is from the Sun. Most known extrasolar planets reside inside the equivalent of Mercury’s orbit.
The planet is estimated to be about five and a half times as massive as Earth and thought to be rocky. It orbits a red dwarf star about 28,000 light-years away. Red dwarfs are about one-fifth as massive as the Sun and up to fifty times fainter. But they are among the most common stars in the universe.
"The team has discovered the most Earth-like planet yet,” said Michael Turner, assistant director for the mathematical and physical sciences directorate at the National Science Foundation, which supported the work.
Prior to this discovery, the smallest extrasolar planet found around a normal star was about seven and a half times earths mass . Earth-sized planets have been detected, but only around dying neutron stars
The newfound planet, named OGLE-2005-BLG-390Lb, is probably too cold to support life as we know it, astronomers said. It has a temperature of -364 degrees ferenheit, nearly as cold as pluto.
The planet and star are separated by roughly 2.5 Astronomical Units. One AU is equal to the distance between the Earth and the Sun. Until now, no small planet had been found farther than 0.15 au from its parent star.
The finding means planet hunters are one step closer to detecting their "Holy Grail": a habitable Earth-like planet that can sustain liquid water and support life.
"We may predict with reasonable probability that microlensing will discover planets with masses like that of Earth at a similar distance from their stars and with comparable surface temperature," said study co-author Bohdan Paczynski from Princeton University.
Of the more than 150 planets have been discovered so far, most were found using the Doppler technique, in which astronomers look for wobbles in a star caused by the gravitational pull of a planet. This method has found dozens of huge worlds but cannot spot small planets that are far from their stars.
Astronomers announced today the discovery of what is possibly the smallest planet known outside our solar system orbiting a normal star.Its orbit is farther from its host star than Earth is from the Sun. Most known extrasolar planets reside inside the equivalent of Mercury’s orbit.
The planet is estimated to be about five and a half times as massive as Earth and thought to be rocky. It orbits a red dwarf star about 28,000 light-years away. Red dwarfs are about one-fifth as massive as the Sun and up to fifty times fainter. But they are among the most common stars in the universe.
"The team has discovered the most Earth-like planet yet,” said Michael Turner, assistant director for the mathematical and physical sciences directorate at the National Science Foundation, which supported the work.
Prior to this discovery, the smallest extrasolar planet found around a normal star was about seven and a half times earths mass . Earth-sized planets have been detected, but only around dying neutron stars
The newfound planet, named OGLE-2005-BLG-390Lb, is probably too cold to support life as we know it, astronomers said. It has a temperature of -364 degrees ferenheit, nearly as cold as pluto.
The planet and star are separated by roughly 2.5 Astronomical Units. One AU is equal to the distance between the Earth and the Sun. Until now, no small planet had been found farther than 0.15 au from its parent star.
The finding means planet hunters are one step closer to detecting their "Holy Grail": a habitable Earth-like planet that can sustain liquid water and support life.
"We may predict with reasonable probability that microlensing will discover planets with masses like that of Earth at a similar distance from their stars and with comparable surface temperature," said study co-author Bohdan Paczynski from Princeton University.
Of the more than 150 planets have been discovered so far, most were found using the Doppler technique, in which astronomers look for wobbles in a star caused by the gravitational pull of a planet. This method has found dozens of huge worlds but cannot spot small planets that are far from their stars.
posted by Bryan Posey-Weekly at 9:58 AM
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