December 2023 – Page 18 – My WordPress Site

Above: Examples of typical surfaces of the icy Galilean satellites (panel a: Europa, near Conamara Chaos region at 8.1°N/90.9°E; panel b: Ganymede, Nicholson Regio at ∼14°S/12.7°E; panel c: Callisto, detail of Asgard impact basin at 14.7°N/218°E). All images are scaled to 150 m px−1. The crater density (a proxy of surface age) increases from Europa to Callisto, reflecting the geological history of surface processes. The surface of Europa displays the most complex inventory of landforms that were formed by endogenic processes, whereas Callisto’s surface is almost devoid of any evidence for tectonic and cryovolcanic activity (Image: NASA/DLR). Below: Models of the interiors of the icy Galilean satellites (Images: ESA/ATG Medialab). Details on their examination by JUICE are provided by Van Hoolst et al. (2024, this collection) -- pace Sci Rev via PubMed

AI - Data - Apps - Cybernetics, Biochemistry & Organic Chemistry, Biophysics, Nanotechnology & SynBio

Google DeepMind Adds Nearly 400,000 New Compounds To Berkeley Lab’s Materials Project

by Keith CowingDecember 2, 2023December 2, 2023

Four stages of planet formation via core accretion and its schematic diagram. Top: Sequential accretion of gas and solid divides the mass growth of planets into four stages. In Stage I, planetary cores form by solid accretion. As time goes on, solid accretion rates decrease, and gas accretion becomes dominated. One conservative estimate of a characteristic solid accretion rate is 10M⊕/1 Myr ∼ 10−5M⊕ yr−1 as denoted by the black dash-dotted line. Once the solid accretion rate becomes lower the value, gas accretion comes into play. In Stage II, accretion of both gas and solids occurs. The gas accretion rate is regulated by cooling of accreted gas (i.e., M˙ XY,KH denoted by the blue solid line). In Stage III, gas accretion is controlled by disk evolution. The corresponding rate becomes very high (i.e., M˙ XY,hydro denoted by the green dotted line), and it is the main channel of forming sub-giants. In Stage IV, gas accretion is reduced due to planet-disk interaction and the resulting gap formation in gas disks (i.e., M˙ XY,gap denoted by the yellow dashed line). This is the final stage of giant plane formation. Mathematical expressions of accretion rates are summarized in Appendix A. Bottom: Sequential accretion of gas and solid can be idealized by the onion-like model. As we show below, bulk and atmospheric metallicities can be used to trace when gap formation in both planetesimal and gas disks occurs, which corresponds to Stages III and IV, respectively. The purple and light salmon trapezoids represent gas and planetesimals disks, respectively. The brown circles denotes solids and the circular rings represent envelope gas. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy

A Resonant Sextuplet Of Sub-Neptunes Transiting The Bright Star HD 110067

by Keith CowingDecember 2, 2023December 2, 2023

Microgravity, Space Life Science, Space Stations, SPACELINE Current Awareness List

NASA Spaceline Current Awareness List #1,077 – 1 December 2023 (Space Life Science Research Results)

by Keith CowingDecember 1, 2023February 9, 2024