Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact

On 26 September 2022 the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, a satellite of the asteroid 65803 Didymos. Because it is a binary system, it is possible to determine how much the orbit of the satellite changed, as part of a test of what is necessary to deflect an asteroid that might threaten Earth with an impact. In nominal cases, pre-impact predictions of the orbital period reduction ranged from ~8.8 - 17.2 minutes. Here we report optical observations of Dimorphos before, during and after the impact, from a network of citizen science telescopes across the world. We find a maximum brightening of 2.29 $\pm$ 0.14 mag upon impact. Didymos fades back to its pre-impact brightness over the course of 23.7 $\pm$ 0.7 days. We estimate lower limits on the mass contained in the ejecta, which was 0.3 - 0.5% Dimorphos' mass depending on the dust size. We also observe a reddening of the ejecta upon impact.Comment: Accepted by Natur

Structure and phylogeny of the crustacean hyperglycemic hormone and its precursor from a hydrothermal vent crustacean: the crab Bythograea thermydron.

International audienceThe structure of a well-known neurohormone involved in homeostasis regulation and stress response, the crustacean hyperglycemic hormone, was investigated in the deep-sea hydrothermal vent crab Bythograea thermydron. The neuropeptide was isolated from neurohemal organs (sinus glands) and its biological activity checked using an homologous bioassay. Partial amino acid sequence was established by a combination of Edman chemistry and mass spectrometry. Then, the sequence of the cDNA encoding the hormone precursor was determined. The preprohormone is composed of a 29 amino acid signal peptide, followed by a 41 amino acid associated peptide flanking the 72 amino acid hyperglycemic hormone. Comparison of these data with other known crab hyperglycemic hormone and prohormone sequences was performed using phylogenetic analysis methods

L'abbatiale Ste Foy de Conques (Aveyron, France) : de l'édifice à son environnement, une approche intégrée

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Enantioselective platinum-catalyzed tandem hydroarylation- cycloisomerization of 1,6-enynes

The platinum(II) chloride/silver hexafluoroantimonate (PtCl2/AgSbF6) catalytic system associated with atropisomeric ligand Ph-BINEPINE promotes a stereoselective tandem hydroarylation (Friedel-Crafts-type addition) of electron-rich aromatic and heteroaromatic derivatives to unactivated alkenes followed by a CC bond cyclization reaction (ee up to 96%). Some evidence shows that the catalytic species responsible for the highest enantiomeric excesses might reasonably be an L3Pt2+ species, L being a monodentate ligand

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