[Report] Thermal and mechanical properties of the near-surface layers of comet 67P/Churyumov-Gerasimenko

Thermal and mechanical material properties determine comet evolution and even solar system formation because comets are considered remnant volatile-rich planetesimals. Using data from the Multipurpose Sensors for Surface and Sub-Surface Science (MUPUS) instrument package gathered at the Philae landing site Abydos on comet 67P/Churyumov-Gerasimenko, we found the diurnal temperature to vary between 90 and 130 K. The surface emissivity was 0.97, and the local thermal inertia was 85 ± 35 J m−2 K−1s-1/2. The MUPUS thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength. A sintered near-surface microporous dust-ice layer with a porosity of 30 to 65% is consistent with the data. Authors: T. Spohn, J. Knollenberg, A. J. Ball, M. Banaszkiewicz, J. Benkhoff, M. Grott, J. Grygorczuk, C. Hüttig, A. Hagermann, G. Kargl, E. Kaufmann, N. Kömle, E. Kührt, K. J. Kossacki, W. Marczewski, I. Pelivan, R. Schrödter, K. Seiferlin

from Science: Current Issue
http://www.sciencemag.org/content/349/6247/aab0464.summary?rss=1

Comments

Post a Comment

Popular posts from this blog

Yu Founder On Next Flagship and Open Source Model for Upcoming Smartphones

Image
Micromax subsidiary Yu Televentures is gearing up to launch its next flagship smartphone this month. Ahead of the launch, company founder Rahul Sharma spoke to Gadgets 360 about the company's strategy for upcoming smartphones and the relationship with Cyanogen. He confirmed that the upcoming Yu flagship will run Android with some customisations from the company, and not Cyanogen , as seen on its predecessor. Sharma revealed that the company has so far sold 2 million devices since Yu established itself as an independent brand, with a new flagship smartphone expected to launch later this month. Talking about the upcoming smartphone, Sharma said that the company will be focusing on offering "pure Android experience" with a deep integration of Around Yu , a service aggregator platform that was introduced last year alongside the Yutopia flagship. He further hinted that the Around Yu will come with some new features. "When we got Cyanogen things were moving fine but ...
Read more

Meet the Site That Is Like Uber - but for Tractors

Image
Jordan Hickel has a long row of ultra-expensive tractors and other machinery parked on his farm in central Kansas. "There's well over a million dollars of equipment out here," the 31-year-old farmer said, waving his hand at the vehicles while walking toward the crown jewel of his collection: A bright red 8120 CASE IH combine that he uses to harvest corn, soybeans, alfalfa and wheat. But Hickel uses the towering machine only two months out of the year. This summer, he's shipping the combine off to Colorado then Washington state - renting it out to other farmers through a website that hopes to bring the sharing economy to the farmstead. Think Uber - but for tractors. The site, MachineryLink Sharing , is the brainchild of a Kansas City company that started about 15 years ago as a traditional combine leasing business. Last year it launched the website that helps farmers make money by renting their equipment to those who can't afford the cost of buying the machi...
Read more