Asteroids

8-micron grain from the Murchison meteorite (Image courtesy Janaína N. Ávila)

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An article published in the journal “Proceedings of the National Academy of Sciences” reports the dating of grains of silicon carbide that were part of the Murchison meteorite, which date back to different times with the oldest one dating back about 7 billion years ago. A team of researchers led by Philipp Heck of the University of Chicago analyzed particles contained in the Murchison meteorite by examining the elements contained and in particular the neon isotopes produced by galactic cosmic rays that struck those grains over time.

A fragment of Muonionalusta meteorite

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An article published in the journal “Nature Astronomy” reports an analysis of the isotopic composition of six groups of iron meteorites, and the results offer evidence that some of the materials that formed the planet Earth came from red giant stars. Mattias Ek of the University of Bristol, Alison C. Hunt, Maria Lugaro and Maria Schönbächler examined in particular the isotopic composition of palladium finding that some dust has a composition that can be produced only by nuclear reactions that take place in red giants’ inner regions. This offers an explanation of the greater presence of that type of dust on Earth than on Mars or in asteroids.

Asteroid Ryugu (Photo courtesy JAXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST)

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The Japanese space agency JAXA has confirmed that its Hayabusa 2 space probe has left asteroid Ryugu, reached on June 27, 2018. Until November 19 it will keep on taking pictures of Ryugu, a limit due to the fact that subsequently a maneuver needed to use its ion engine will lead it to turn into a position from which it will no longer have the asteroid in its camera’s view. Until that day, it will be possible to send a farewell message to Ryugu via Twitter or even letters and postcards to JAXA. Hayabusa 2 is scheduled to return near the Earth with its samples near the end of 2020.

Asteroid Hygiea is spherical and could be reclassified as a dwarf planet

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An article published in the journal “Nature Astronomy” reports a study of asteroid Hygiea that shows its roughly spherical shape, one of the requirements to be cataloged as a dwarf planet. A team of researchers led by Pierre Vernazza of the Laboratoire d’Astrophysique of Marseille, France, used the SPHERE instrument mounted on ESO’s VLT in Chile to obtain detailed images of one of the largest objects in the asteroid belt between Mars and Jupiter. If Hygiea were reclassified, it would be the smallest dwarf planet with a diameter that is less than half that of Ceres.

Photo of asteroid Ryugu's soil taken by the ONC-W1 camera (Photo courtesy JAXA. All rights reserved)

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A few hours ago the Japanese space probe Hayabusa 2 touched down on the soil of asteroid Ryugu to collect some subsurface samples that will be transported to Earth. This is the second attempt of the three possible at the start of the mission. After the first sample taken on February 22, 2019, the Japanese space agency JAXA decided to proceed with a second attempt in another area to then finish Ryugu’s study and return to Earth with the samples taken.