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The ashes of a dying star contain clues about the birth of our solar system



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Grain dust forged in the agony of that old star has been discovered by a research team led by the University of Arizona.

Identification of the problem some of the current theories of how stars die to seed the universe with raw materials for the formation of planets and, ultimately, the precursor molecules of life.

Hidden inside chondrite meteorite collected in Antarctica, a tiny speck of Stardust is actual, likely tossed into the space of the exploded star, before there was our sun. Although these herbs are supposed to & # 39 is an important raw material, which contribute to the mixture, which our Sun and planets form, they rarely survive the hustle and bustle that comes with the birth of the solar system.

"As the actual dust from stars such presolar grains give us an idea of ​​the building blocks from which formed our solar system," said P & # 39; er Haenecour, lead author of the article, which is scheduled for advance online publication on the site Nature Astronomy to 29 April . "They also give us a direct image of the star in terms of the time it was formed by the grain."

Dubbed the LAP-149, a dust grain is a single assembly known graphite and silicate grains, which can be traced to a specific type of stellar explosion called new. It is remarkable that he survived the journey through interstellar space, and went to the region, which will be our solar system about 4.5 billion years ago, perhaps earlier, where it has become embedded in the primitive meteorite.

Novae binary star systems in which the main remnant of a star, called a white dwarf, is on track to fade from the universe, while his companion or low-mass main sequence star and a red giant. The white dwarf then starts to siphon material from its bloated companion. After he heals fairly new stellar material of white dwarf again ignited in periodic outbreaks of violent enough to forge new chemical elements in stellar fuel and emit them deeply into space, where they can travel to new star systems and become incorporated into their raw materials,

Indeed, shortly after the Big Bang, when the universe consisted of only hydrogen, helium and traces of lithium, stellar explosions helped to enrich the chemical space, resulting in a set of elements that we see today.

Using complex ion and electron microscopy on the & # 39 objects on the Lunar and Planetary Laboratory of the user agent, the research team led by Haenecour analyzed the microbe-sized dust grains down to the atomic level. Tiny messenger from space turned out to be really alien – highly enriched isotope of carbon called 13C.

"The carbon isotopic compositions in all we ever taken away, who had come from any planet or bodies in our solar system, usually depends on the order of a factor of 50," said Haenecour, who will join the laboratory of the moon and the planet as an Assistant Professor fall. "13C we found in the LAP-149 enriched with more than 50,000 times. These results provide further laboratory evidence that both carbon- and oxygen-enriched grains of new stars contributed a building block of our solar system. "

Although their parent star no longer exist, the isotopic and chemical compositions and microstructure StarDust individual grain identified in meteorites provide unique restrictions on the linting and thermodynamic conditions in stellar outflow authors write.

Detailed analysis has shown even more unexpected secrets: Unlike similar grains believed to have been tampered with in the die stars, LAP-149 & # 39 is the first known grain consisting of graphite, comprising including silicates enriched oxygen.

"Our discovery gives us a glimpse into the process, we could never be evidence of the Earth," added Haenecour. "This tells us how a speck of dust form and move inside, they expelled the supernova. We now know that the carbonate and silicate dust particles may be formed in the same new star ejected, and they get transported through the chemically different dust clots within of Ejecta, what was predicted by the model of new stars, but not found in the sample. "

Unfortunately, LAP-149 does not contain a sufficient number of atoms to determine its exact age, so the researchers hope to find a similar, larger samples in the future.

"If we could date these on & # 39; objects ever, we could get a better idea of ​​what our galaxy looked like in our region, and that has caused the formation of the solar system," said Tom Zega, supervisor of the user agent Kuiper materials for imaging and characterization of the Fund and an assistant professor of the Lunar and planetary laboratory and UA materials science and engineering. "Perhaps we owe our existence to the nearest supernova explosion, a cloud of gas and dust from his shock, igniting the star and creating stellar nursery, similar to what we see in the famous" Pillars of Creation "picture Hubble."

Meteorite containing a speck of Stardust & # 39 is one of the most pristine meteors per month and collections Planetary Laboratory. Classified as a carbon chondrite, it is believed to be similar to the material of the target asteroid Benny on UA-led mission OSIRIS-REX. Taking a sample of Benny and bring it back to Earth, the team's mission OSIRIS-REX hopes to give scientists the material, which has seen little, if any, changes since the formation of our solar system.

By that time, the researchers did not depend on the rare finds, as the LAP-149, who survived being blasted from the exploded star, caught in destroying the cloud of gas and dust, which will be our solar system, and baked in an asteroid before falling to the ground.

"It's great when you think about all the ways along the way, which was to kill the grain," said Zega.

link:
"Laboratory data on cooperation condensed oxygen- and carbon-Rich meteorite Stardust with new outbreaks," Pierre Haenecour et al., April 29, 2019, Nature Astronomy [https://www.nature.com/articles/s41550-019-0757-4].

Support for this study was provided by organizations including NASA and the National Science Foundation, which also supports the UA Kuiper imaging material and characterization of the Fund, which made a detailed sample LAP-149 analysis capabilities.

Founded in 1885, University of Arizona, the state of super land grant university from two medical schools produce graduates who are ready in the real world as part of its initiative 100% participation. Recognized as the global leader and ranks 16th for the employment of its graduates, and with BVS & # 39; is a leader in research, resulting in more than $ 606 million investment in research each year, and the rating of the twenty-first among all public universities. UA border isolated interdisciplinary science and business partnerships, as well as with the & # 39; is a member of the Association of American Universities, 62 of the leading public and private research universities. It benefits from the state estimated economic impact of $ 8300000000 annually.

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