From: Indy Kochte <kochte@s...>
Date: Wed, 25 Aug 2004 11:25:28 -0400
Subject: [OT] First extrasolar Earth-type planet discovered?
This is OT for most things here, but for the vaccheads, and stellar cartographers, mu Arae likely has several planets around it, including this new large probably rocky planet. For the grunts and dirtsiders, this gives Jon Davis' "Hot Spot" scenario (DSII, run at GZG ECC several years consecutively) some validity. :-) And as Beth can tell you, life has been found in some pretty non-hospitable- to-life regions on our own planet. Who knows what is living there... Mk (in other extrasolar planet news, there was an announcement earlier this morning from the Lowell Observatory about their discovering a new exo-planet using 4-inch telescopes - what does that say for astro- cartographers of the GZGVerse for discovering new K'V worlds? ;-) ----------------------- http://www.space.com/scienceastronomy/super_earth_040825.html Super Earth' Discovered at Nearby Star By Robert Roy Britt Senior Science Writer posted: 25 August 2004 10:06 am ET European astronomers have discovered one of the smallest planets known outside our solar system, a world about 14 times the mass of our own. It could be a rocky planet with a thin atmosphere, a sort of "super Earth," the researchers said today. This is no typical Earth, however. It completes its tight orbit in less than 10 days, compared to the 365 required for our year. Its daytime face would be scorched. It is not possible to know exact surface conditions of the planet, said Portuguese researcher Nuno Santos, who led the discovery. "However, we can expect it to be quite hot, given the proximity to the star." Hot as in around 1,160 degrees Fahrenheit (900 Kelvin), Santos told SPACE.com. Still, the discovery is a significant advance in technology that reveals a solar system slightly similar to our own in ways not seen until now. The star is similar to our Sun and just 50 light-years away. A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers). Most of the known planets beyond the nine we're most familiar with are hundreds or thousands of light years distant. The star, mu Arae, is visible under dark skies from the Southern Hemisphere. It harbors two other planets. One is Jupiter-sized and takes 650 days to make its annual trip around the star. The other is farther out and was confirmed to exist by the new observations. Nearly all of the more than 120 planets found beyond our solar system are gaseous worlds as big or larger than Jupiter, mostly in tight orbits that would not permit a rocky planet to survive. Search techniques have so far not allowed the discovery of anything smaller than Saturn around Sun-like stars. A trio of roughly Earth-sized planets was found to orbit a dense corpse of star known as a neutron star. They are oddballs, however, circling rapidly around a dark star that would not support life. Some planet hunters don't consider these three to be as important as planets around normal stars. At 14 times the mass of Earth, the newfound planet -- circling a star similar in size and brightness to our Sun -- is about as heavy as Uranus, a world of gas and ice. Theorists say 14 Earth-masses is roughly the upper limit for a planet to possibly remain rocky, however. And because this planet is so close to its host star, it likely had a much different formation history than Uranus. In our solar system, the four innermost planets are all rocky. The leading theory of planet formation has the gas giants forming from a rocky core, a process in which the core develops over time, then reaches a tipping point when gravity can rapidly collect a huge envelope of gas. This theory suggests the newfound planet never reached that critical mass, said Santos, of the Centro de Astronomia e Astrofisica da Universidade de Lisboa, Portugal. "Otherwise the planet would have become much more massive," Santos said via e-mail. "This object is therefore likely to be a planet with a rocky core surrounded by a small gaseous envelope and would therefore qualify as a super-Earth," the European team said in a statement. The discovery was made with a European Southern Observatory telescope at La Silla, Chile. There are no conventional pictures of the object, as it was detected by noting it gravitational effect on the star. The search project leading to the discovery is led by Michel Mayor of the Geneva Observatory in Switzerland. While researchers do not know the full range of conditions under which life can survive, the newly discovered world, with its hot surface, is not the sort of place biologists would expect to find life as we know it. Santos said life on the world is not likely. But, he added, "one never knows."