July 1, 2014
Early Sun’s Violent Beginnings May Have Unlocked The Mystery Of Milky Way Meteorites
Gerard LeBlond for redOrbit.com - Your Universe Online
Astronomers are studying young stars in faraway areas of the galaxy, discovering they have a violent beginning, much as our own sun did 4.5 billion years ago. Herschel is surveying the chemical composition of stars being born and a team of astronomers discovered a different object in the region. OMC2 FIR4 is a cluster of new stars within a gaseous dust cloud in the Orion Nebula.
“To our great surprise, we found that the proportion of two chemical species, one based on carbon and oxygen and the other on nitrogen, is much smaller in this object than in any other protostar we know,” says leader of the study Dr Cecilia Ceccarelli, of the Institute de Planétologie et d’Astrophysique de Grenoble, France, along with Dr Carsten Dominik of the University of Amsterdam in the Netherlands.
In cold environments it is possible for one of two compounds to freeze onto dust grains and go unnoticed. However, OMC2 FIR4 is a high-temperature star-forming region at about 200 degrees Celsius and this should not occur.
“The most likely cause in this environment is a violent wind of very energetic particles, released by at least one of the embryonic stars taking shape in this proto-stellar cocoon,” Dr Ceccarelli adds.
Hydrogen is the most abundant molecule in star-forming clouds and can be broken down by cosmic rays which are flowing in every part of the universe. These hydrogen particles combine with other particles in the region like carbon and oxygen or nitrogen.
The nitrogen compound usually is destroyed quickly allowing more hydrogen to be added to the mix. This process is abundant in all known stellar formations.
However, this is not what happened in OMC2 FIR4; the astronomers believe that an extra strong wind of energetic particles destroyed both chemicals. They also believe that a similar violent event of wind particles ripped through the early Solar System, explaining the origin of particular chemicals found in meteorites.
A meteorite is the remnant of interplanetary debris flowing through space and surviving our atmosphere. These meteorites are an asset in discovering elements of our Solar System.
“Some elements detected in meteorites reveal that, long ago, these rocks contained a form of beryllium: this is quite puzzling, as we can’t quite understand how it got there,” explains Dr Dominik.
Beryllium-10 is an isotope and its origin in the universe is a mystery on its own. Astronomers know it doesn’t come from the interior of stars, unlike other elements that do. It also doesn’t form from supernova explosions at the end of a star’s existence.
Most of the beryllium-10 is formed by collisions of energetic particles with heavy elements like oxygen. However, isotope decays rapidly so it must have been produced just before it was embedded into the solid rock that later becomes a meteorite when it lands on Earth.
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