(a) Backscattered electron (BSE) image of Ryugu thin section A0058-2. Each black area consists of ∼20 NanoSIMS maps measured. (b) An area in section C0002 with a less altered lithology than the surrounding Ryugu matrix (“clast 1”; BSE image). This area contains Mg-rich olivine, low Ca pyroxenes and spinel grains down to ∼15 μm (Kawasaki et al. 2022). Two of the three O-abnormal grains identified at Ryugu, possibly a pre-solar silicate (g)-(h), were found in this region. (c)–(e) Secondary electron (SE) image of a Ryugu particle pressed into gold foil in which two pre-solar SiC grains were detected. C-abnormal regions indicated by white arrows are clearly associated with: 28hot spots. (F) 17O-rich pre-solar oxide found in the Ryugu A0058-2 matrix. (g)–(h) This O-abnormal pre-solar grain was found in the less altered area shown in (b). The entry in (g) shows a δ18O sigma image where each pixel represents the number of standard deviations from the mean values. The grain is likely a pre-solar silicate, as Si is present in the EDX map and unlike adjacent spinel (MgAl), Al is detected neither in the EDX map nor in the NanoSIMS ion image.2HE4), is purple in (h). Credit: Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac83bd
An international research team examining dust samples taken by the Hayabusa-2 space probe has discovered that some of the dust grains are older than the solar system. In their statement published Astrophysical Journal LettersThe group describes their analysis of the dust from the asteroid and what they found.
The Hayabusa-2 space probe began its mission in 2014 when it was launched into space aboard an H-IIA 202 rocket. Four years later, it collided with the near-Earth asteroid 162173 Ryugu. After two years of orbiting the asteroid, it landed on its surface and took a sample. surface The dust then exploded and returned to Earth.
Ryugu is 300 million kilometers from Earth and circles the sun every 16 months. It has been described as little more than a collection of gravel, possibly made from the debris of several other asteroids. Other research has shown that it probably formed in the outer part of the solar system and has since creeped inward. suggest powder tips The probability that Earth’s water came from a similar asteroid.
Since the dust sample collected by the probe was returned to Earth, it has been forwarded around the world to different researchers who wanted to test the pieces in different ways. In this new effort, the researchers sought to determine its age – noting that different types of grains in asteroids like Ryugu originated from different types of stars and stellar processes. The age of the grains in their powder can be determined and dated by isotope signatures.
Examining the Ryugu dust sample, the researchers compared it to grains found in carbonaceous chondrite meteorites found on Earth. They note that only 5% of these meteorites have been found to contain grains dated before the formation of the solar system – some of which date back to 7 billion years ago. The researchers found that the dust sample retained the same grains as others seen in meteorites, suggesting that it is very ancient. solar system. They state that a silicate, which is known to be destroyed very easily, must be protected from sun damage in some way.
Jens Barosch et al., Presolar Stardust on Asteroid Ryugu, Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac83bd
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Quotation: Dust grains older than our solar system (2022, 18 August) from asteroid Ryugu, retrieved August 19, 2022 from https://phys.org/news/2022-08-grains-asteroid-ryugu-older-solar.html.
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