When the low-mass stars called red supergiants die they disappear on a wimpy wind, or if scientists thought. New research just published, suggests that the opposite may be true. These stars, in fact, may die with a bang and not a whimper. The study, published today in the journal Science, researchers may lead to new understanding of the red supergiants, which are designed to solve the problems of nucleosynthesis, stellar structure and evolution of stars.
This discovery was really a huge surprise, said Dr. Michael Duncan, a research professor of chemistry at the University of Georgia. One of the beauties of doing basic science is that you never know where it might lead. Other authors of the article published in Science, is Gerard Meijer, Gert von Helden, Deniz van Heijnsbergen and the FOM Institute for Plasma Physics in Nieuwegein, AGGM Tiel, University of Groningen and S. Hony and LBFM Waters, University of Amsterdam, all Holland.
During their agony, low mass stars in new red supergiants, which are more properly called asymptotic giant branch stars or AGBs. Indeed, it takes up a certain type of stars, the AGB phase is a relatively short stage in which the low-mass stars are the brightest of them, but seeing a large mass loss that leads quickly to the global stage fog and a final cooling white dwarf.
This discovery was really a huge surprise, said Dr. Michael Duncan, a research professor of chemistry at the University of Georgia. One of the beauties of doing basic science is that you never know where it might lead. Other authors of the article published in Science, is Gerard Meijer, Gert von Helden, Deniz van Heijnsbergen and the FOM Institute for Plasma Physics in Nieuwegein, AGGM Tiel, University of Groningen and S. Hony and LBFM Waters, University of Amsterdam, all Holland.
During their agony, low mass stars in new red supergiants, which are more properly called asymptotic giant branch stars or AGBs. Indeed, it takes up a certain type of stars, the AGB phase is a relatively short stage in which the low-mass stars are the brightest of them, but seeing a large mass loss that leads quickly to the global stage fog and a final cooling white dwarf.
Scientists have studied the AGB stars for a long time, but research has accelerated in recent times, using the Hubble Space Telescope and the European Space Agency's Infrared Space Satellite. Duncan participation in a scientific discovery was serendipity that often lead to unexpected breakthroughs.
His area of research in gas-phase metal clusters, has recently taken a huge step forward, as with Gerard Meijer, who met at a scientific meeting of the Ohio State University, 1998, Meijer and colleagues from the Netherlands .. He spoke of the free-electron laser FELIX is called [Infrared Free-Electron Laser Tuning], which was built at the FOM Institute, and I happened to ask him if he's ever been used to investigate metal cluster gas phase, he Duncan said. Speaking of our collaboration was born.
There is probably no more than 20 free-electron lasers in the world and only five in the U.S. (the priorities for the use of machines in the United States is largely to medical science or industrial uses .) FELIX is the only optimized for measuring signals or infrared spectra of chemicals, and seemed a perfect match for the experiments of metal clusters.
The study of metal clusters have been around for only two decades. Duncan helped launch the field due to a laboratory accident, when he was a doctoral student in chemistry at Rice University with Richard Smalley. Duncan and a doctoral student working on an experiment of molecular beam after laser part misaligned accidentally sprayed the aircraft.
After meeting Meijer, we realized that his team had a free electron laser, and I had pulsed molecular beam machine and the experience of working with metal poles, and we had to find a way to work together, said Duncan. Fortunately, Meijer has received about that time a major grant from the Dutch government, and the team of the Netherlands was able to build molecular beam machine that Duncan had used for the study of metal clusters and companion the free electron laser. The actual construction of the machine beam was monitored by Gert von Helden and Deniz van Heijnsbergen.
The result was a machine capable of detecting the infrared spectra of metals in the gas phase and thus provide important clues about how they are structured. The new unit has worked flawlessly, and when Duncan visited the lab last summer, the team obtained the first direct infrared spectrum of these groups never did. His work was published in the journal Physical Review Letters.
These spectra in itself is likely to open a new era in the study of how metals in the gas phase is structured, but a chance encounter with other researchers at the Netherlands Institute ODM launched a shocking discovery who led the research laboratory to the stars. These astronomers have visited the facility FELIX and hear about the work of polycyclic aromatic hydrocarbons, which are important in the composition of interstellar space, "said Duncan.
After meeting Meijer, we realized that his team had a free electron laser, and I had pulsed molecular beam machine and the experience of working with metal poles, and we had to find a way to work together, said Duncan. Fortunately, Meijer has received about that time a major grant from the Dutch government, and the team of the Netherlands was able to build molecular beam machine that Duncan had used for the study of metal clusters and companion the free electron laser. The actual construction of the machine beam was monitored by Gert von Helden and Deniz van Heijnsbergen.
The result was a machine capable of detecting the infrared spectra of metals in the gas phase and thus provide important clues about how they are structured. The new unit has worked flawlessly, and when Duncan visited the lab last summer, the team obtained the first direct infrared spectrum of these groups never did. His work was published in the journal Physical Review Letters.
These spectra in itself is likely to open a new era in the study of how metals in the gas phase is structured, but a chance encounter with other researchers at the Netherlands Institute ODM launched a shocking discovery who led the research laboratory to the stars. These astronomers have visited the facility FELIX and hear about the work of polycyclic aromatic hydrocarbons, which are important in the composition of interstellar space, "said Duncan.
It turns out that our work on the metal in the gas phase was on a machine nearby, and asked what it was. Helden von Meijer and showed them the machine and the spectra we had. It is when their mouths agape. Astronomers led by Alexander Tiel University Groningen, realized immediately that the infrared spectra that the group had developed from their study of nanocrystals of titanium carbide corresponded almost exactly to the spectra of unknown origin seen time and again in AGB stars. The discovery has created a problem , however.
Meteorites contain grains of micrometer-sized graphite with embedded titankarbid (ICT) grains were found on Earth. Isotopic analysis has identified AGB stars as the cradle of these nuclei, although there was no direct correlation. Astronomers believe that AGB stars begin to die, newly synthesized elements ICT is mixed to the surface where they spread through the galaxy in a wind, usually in the form of stardust.
The problem lies in the abundance of titanium in low-mass stars is so low that high density just need to get a high gain collision enough to reach the size observed in graphite Stardust. For about 20 years, scientists have believed in a phase called super-wind occurs when those stars are spectacular loss of mass. But the super-wind phase, despite its name, was considered a relatively modest event where the star is the stellar envelope is blown.
Identification of the infrared spectrum around AGB stars, the gas-phase titanium, however, the image change. Since small amounts of titanium in the stars and the large number of shells if they need to create something creative, which releases enormous energy in a relatively short period of time. Or, as the authors write, the identification of ICT, rather than the wimpy wind, low-mass stars end their lives (almost) a bang. Studies infrared spectra of AGB stars has just begun to take off. Conference in France in 1998 were reported in the first so-called mature results of the study. New research has added fuel to the fire of speculation about how the stars formed, how they live, and ultimately how they die.
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