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Title - The Poles and Shapes of Seven Kuiper Belt Objects as Measured from New Horizons
By - Simon Porter et al, 2022
Summary - KBOs spin on their sides / Pancakes or bowling pins / New Horizons can see.
"Studies of asteroid lightcurves demonstrate that the amplitude of elongated objects increases at higher phase angles, whereas the amplitude remains the same for spherically shaped objects."
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Title - Yilan crater, China: Evidence for an origin by meteorite impact
By - Ming Chen et al, 2021
Summary - Despite its size, Yilan Crater in China was not clearly recognized as an extraterrestrial impact until 2021.The Yilan crater is 1.85 km in diameter and 579 meters in depth. Only the southern third of the crater rim is missing, while the other rim sections are all well preserved, with a maximum elevation above the present crater floor of 150 meters.
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Title - Geologically rapid aqueous mineral alteration at subfreezing temperatures in icy worlds
By - Zandanel et al, Mar 2022 (Paywalled)
Summary - Contrary to usual assumptions, you don't need above 0°C temperatures for aqueous alteration. Aqueous alteration can still be efficient and geologically quick at -20 °C within the cores of large icy worlds, due to the presence of alkaline solutions containing salts and ammonia.
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Title - The origin of volatile elements in the Earth–Moon system
By - Lars Borg et al, Feb 2022
Summary - "Earth was either born with the water we have, or we were hit by something that was basically pure H2O, with not much else in it. This work eliminates meteorites or asteroids as possible sources of water on Earth and points strongly toward the 'born with it' option," - cosmochemist Greg Brennecka, co-author of the paper.
News - Phys.org
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Title - Distribution of ejecta from small impact craters
By - Valery Shuvalov et al, 2013
Summary - Ejecta can roughly be divided into two categories: “ballistic” ejecta and “convective” ejecta; the ballistic ejecta are the ejecta with which the air interacts only slightly, while the convective ejecta motion is entirely defined by the air flow. The degree of particle/air interaction can be defined by the time/length of particle travel before deceleration.
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Title - Ejecta from impact craters
By - K. Housen et al, 2010
Summary - Laboratory measurements of impact crater ejecta from 18 studies are summarized in this study. The effects of impact speed on the ejecta are reasonably well understood, but the dependences on target properties such as strength and porosity are only poorly constrained.
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By - A. J. Verbiscer et al, Mar 2022
Summary - New Horizons observed cold classical KBOs 2014 PN70, 2014 OS393, 2011 HF103, 2011 HZ102, 2011 JY31 & 2011 JX31 from distances as small as 0.09 au at multiple solar phase angles between 19° and 122°. Rotation periods range from 12.05 hours to more than 35 hours. The amplitudes of most CC KBO rotation curves increase with increasing solar phase angles, likely due to their irregular shapes. Binary CC KBO 2011 JY31, however, has a low amplitude (0.2 mags) rotation curve that does not increase in amplitude with increasing phase angle.
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Title - Sub-Seasonal Variation in Neptune's Mid-Infrared Emission
By - Michael T. Roman et al, April 2022
Summary - Despite Neptune's summertime starting in 2005, its global temperatures dropped by 8 °C between 2003 and 2018 (dramatic cooling), followed by a dramatic warming at its south pole by 11 °C. This drastic climate change was very unexpected & its cause remains unknown. A Neptune season lasts around 40 years, with one Neptune year lasting 165 Earth years.
News - Phys.org
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Title - Planetesimal formation around the snow line. Dust or pebbles?
By - Ryuki Hyodo et al 2021
Summary -
News - JAXA
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Article - Volatile’ elements in inner solar system have several different origins
Date - Feb, 2023
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Title - Origin of life-forming volatile elements in the inner Solar System
By - Michael Broadley et al, Nov 2022
Summary -
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By - Christopher Hamann et al, 2023
Summary - Intense shear deformation during crater formation results in significant but highly localized heating that can form thin melt veins.
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By - Larry Nittler et al, June 2023
Summary - Data returned by NASA's MESSENGER mission, which orbited Mercury from 2011-2015, have shown that the innermost planet formed under highly reducing (relatively low-oxygen) conditions, compared to the other terrestrial planets, but estimates of Mercury's oxidation state are highly uncertain. Chromium, a minor element in planetary materials, can exist in a wide range of oxidation states and its abundance thus can provide information about the chemical conditions under which it was incorporated into rocks.
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Title - Iodine/Plutonium reveals Earth mainly accreted from volatile-poor differentiated planetesimals
By - Weiyi Liu et al, 2023
Summary - Mid-ocean ridge basalts had 3X higher iodine/plutonium ratios (inferred from xenon isotopes) compared to ocean island basalts. Based on these chemical ratios, a model was created that showed Earth formed from hot, dry, rocky materials, and that, a major addition of life-essential volatiles, including water, only occurred during the last 15% (or less) of Earth's formation from late accretion of chondrites, with a notable carbonaceous chondrite contribution.
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By - Greenwood et al, 2023
Summary - Winchcombe is one of the least terrestrially contaminated Carbonaceous Chondrite (CC) in our collections. Winchcombe is a complex breccia comprising 8 distinct lithological units, each showing variable degrees of aqueous alteration (CM2.0–CM2.6). In addition, there is also a cataclastic matrix that encloses the different fragment types. There have been only 21 officially authenticated CM2 falls, including Winchcombe, since 1838, representing just 1.7% of all recovered falls (hence, very rare). The total amount recovered stands at 602 g, comprising hundreds of pieces, as per wiki. Winchcombe meteorite's parent body experienced extensive aqueous alteration. The style of alteration exhibited by Winchcombe is consistent with relatively closed system processes. (The CM2 group is classified as petrologic type 2 and indicates that the matrices of these meteorites are essentially fully hydrated, with various degrees of hydration of the chondrules - wiki).
Cr Isotopes in the Winchcombe meteorite samples are close to other CM2 chondrites. ε53Cr = 0.319 and ε54Cr = 0.775. There is a significant overlap between CO and CM chondrites, both in terms of ε50Ti and ε54Cr. CMs and COs may also be indistinguishable with respect to Ti and Cr isotopes. In a solar-sized star, the snow line is generally located at a distance of less than 5 AU and migrates inward with time. However, as directly imaged by ALMA during high energy outbursts seen in young, embedded stars, it can jump outward to 40 AU. Planetesimal formation immediately outside of the paleo snow line is unlikely to have been a single, isolated event and hence in theory, multiple CM parent bodies with very similar compositions could have formed in this environment. Conclusion - CMs and COs may also be indistinguishable with respect to Ti and Cr isotopes.
News - Tweet about paper,
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Title - The Winchcombe meteorite, a unique and pristine witness from the outer solar system
By - Ashley King et al, 2022
Summary - Carbonaceous chondrites are highly susceptible to alteration in the terrestrial environment and extraterrestrial signatures can be modified within days. However, with the first material recovered within hours of the fall, the Winchcombe meteorite is the least terrestrially modified member of the CM chondrite group recovered to date. The Winchcombe meteorite contains abundant hydrated silicates formed during fluid-rock reactions, and carbon-bearing and nitrogen-bearing organic matter, including soluble protein amino acids.
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Title - The fusion crust of the Winchcombe meteorite: A preserved record of atmospheric entry processes
By - Matthew Genge et al, 2023
Summary - Observations on the fusion crust of Winchcombe reveal that several previously unknown processes occur during atmospheric flight. Interestingly, the most unusual features of Winchcombe fusion crust, namely the large abundance of dehydration cracks, are likely to have indigenous origins related to material properties of the meteoroid, rather than its entry parameters. The mineralogy and composition of its matrix are evidently highly susceptible to contraction of dehydration of clay minerals and tochilinite compared to most other carbonaceous chondrites.
News - Tweet about paper,
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Title - Webb detects water vapour in rocky planet-forming zone
By - ESA, July 2023
Summary - .
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Title - Geophysics and origin of the Deniliquin multiple-ring feature, Southeast Australia
By - Glikson & Yeates, 2022
Summary - Deniliquin is a impact crater in Australia. For perspective, the Chicxulub crater is estimated to be 180 km in diameter & the Vredefort impact crater is 160 km in diameter..
News - Asteroid crater 520 km in diameter buried deep in southeast Australia, scientists say
World’s largest asteroid impact may be buried in Australia
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