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Earth's solid surface and moderate climate may be due, in part, to a massive star in the birth environment of the Sun, according to new computer simulations of planet formation. Without the star's radioactive elements injected into the early solar system, our home planet could be a hostile ocean world covered in global ice sheets."The results of our simulations suggest that there are two qualitatively different types of planetary systems," said Tim Lichtenberg of the National Centre of Competence in Research PlanetS in Switzerland. "There are those similar to our solar system, whose planets have little water, and those in...

Martin Bizzarro of the University of Copenhagen and his colleagues set out to determine the amount of iron in the early solar system. To do so, they measured nickel-60, a decay product of iron-60, in eight meteorites known to have formed at different times during the first 3 million years of the solar system. The meteorites that formed more than about a million years after the start of the solar system contain significantly more nickel-60 than do those that formed earlier, the team found. In a neighborhood of young stars, only a supernova could have produced iron-60, the parent of...

A strange mix of oxygen found in a stony meteorite that exploded over Pueblito de Allende, Mexico nearly 40 years ago has puzzled scientists ever since. Small flecks of minerals lodged in the stone and thought to date from the beginning of the solar system have a pattern of oxygen types, or isotopes, that differs from those found in all known planetary rocks, including those from Earth, its Moon and meteorites from Mars. Now scientists from UC San Diego and Lawrence Berkeley National Laboratory have eliminated one model proposed to explain the anomaly: the idea that light from the early...

The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the exoplanets. Analogs to our own solar system do not appear to be common, originating from disks near the boundary between barren and (giant) planet-forming.

Source:   University Of Missouri-Rolla (http://www.umr.edu) Date:   Posted 7/17/2002 The Sun: A Great Ball Of Iron? For years, scientists have assumed that the sun is an enormous mass of hydrogen. But in a paper presented before the American Astronomical Society, Dr. Oliver Manuel, a professor of nuclear chemistry at UMR, says iron, not hydrogen, is the sun's most abundant element. Manuel claims that hydrogen fusion creates some of the sun's heat, as hydrogen -- the lightest of all elements -- moves to the sun's surface. But most of the heat comes from the core of an exploded supernova...

...in a new study, published in the Astrophysical Journal, researchers from the University of Chicago... suggest that our solar system formed billions of years ago in a vast "bubble" of gas and dust around a giant, long-dead star, contradicting the commonly held view which suggests a nearby supernova was responsible... The dead star in question is what scientists call a Wolf-Rayet star. These are more than 40 to 50 times the size of our own Sun and burn hotter than any other stars, producing vast quantities of material -- much of which is blown off the surface by intense stellar...

Explanation: Might this giant pinwheel one-day destroy us? Probably not, but investigation of the unusual star system Wolf-Rayet 104 has turned up an unexpected threat. The unusual pinwheel pattern has been found to be created by energetic winds of gas and dust that are expelled and intertwine as two massive stars orbit each other. One system component is a Wolf-Rayet star, a tumultuous orb in the last stage of evolution before it explodes in a supernova -- an event possible anytime in the next million years. Research into the spiral pattern of the emitted dust, however, indicates the we are...

WASHINGTON (AFP) – A massive bright reddish star in the Orion constellation has mysteriously shrunk by over 15 percent in the last 15 years and astronomers have not yet determined why, according to a study released Tuesday. Betelgeuse, considered a supergiant star, is so large that it would reach to Jupiter's orbit in our solar system. But at a radius of about five astronomical units, the star has shrunk in size since 1993 by a distance equivalent to Venus's orbit. "To see this change is very striking," University of California, Berkley professor Charles Townes, who whon the 1964 Nobel Prize...

Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. Near the center of this intriguing widefield view of interstellar gas clouds and rich star fields of the constellation Cygnus, NGC 6888 is about 5,000 light-years away. The three color composite image was created by stacking exposures through narrow band filters that transmit the light from atoms in the clouds. Hydrogen is shown as green, sulfur as red, and oxygen as blue. NGC 6888's central star is classified as a Wolf-Rayet star (WR...

Explanation: Some stars explode in slow motion. Rare, massive Wolf-Rayet stars are so tumultuous and hot that they slowly disintegrating right before our telescopes. Glowing gas globs each typically over 30 times more massive than the Earth are being expelled by violent stellar winds. Wolf-Rayet star WR 124, visible near the above image center spanning six light years across, is thus creating the surrounding nebula known as M1-67. Details of why this star has been slowly blowing itself apart over the past 20,000 years remains a topic of research. WR 124 lies 15,000 light-years away towards the constellation of Sagitta....

Earth may lie in the path of a dangerous gamma-ray burst that could wipe out a quarter of our atmospheric ozone. Astronomers say that WR 104, a Wolf-Rayet star about 8,000 miles away, could go supernova any day, which would generate gamma-rays that could reach Earth.

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 April 15 A Crescent Nebula Star Field Credit & Copyright: T. A. Rector (NRAO), NOAO, AURA, NSF Explanation: What caused the Crescent Nebula? Looking like an emerging space cocoon, the Crescent Nebula, visible on the right, was created by the brightest star in its center. A leading progenitor hypothesis has the Crescent Nebula beginning to form about 250,000 years ago. At that time, the massive central star...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 April 10 Energized Nebula in the LMC Credit: Y. Naze, G. Rauw, J. Manfroid, J. Vreux (Univ. Liege), Y. Chu (Univ. Illinois), ESO Explanation: Blossoming in nearby galaxy the Large Magellanic Cloud (LMC), this gorgeous nebula is energized by radiation and winds from a massive star whose surface temperature approaches 100,000 degrees. The composite color image from the European Southern Observatory's Melipal telescope resolves details in the...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 March 25 A Slow Explosion Credit: Y. Grosdidier (U. Montreal) et al., WFPC2, HST, NASA Explanation: Why would a gamma ray burst fade so slowly? This behavior, recorded last October, is considered a new clue into the cause of gamma-ray bursts, the most powerful explosions known in the universe. The burst, first detected by the orbiting HETE satellite and later tracked by numerous ground-based telescopes, showed an...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 5 NGC 2359: Thor's Helmet Credit: Christine and David Smith, Steve Mandel, Adam Block (KPNO Visitor Program), NOAO, AURA, NSF Explanation: NGC 2359 is a striking emission nebula with an impressive popular name - Thor's Helmet. Sure, its suggestive winged appearance might lead some to refer to it as the "duck nebula", but if you were a nebula which name would you choose? By any name...