January 2019

Artist’s impression of a planetesimal (Image courtesy Ko Arimatsu / NAOJ. All rights reserved)

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An article published in the journal “Nature Astronomy” reports the discovery of a planetesimal, which is an object of the type that probably formed planets, dwarf planets and asteroids, with an estimated radius of about 1.3 kilometers in the Kuiper Belt. A team led by Ko Arimatsu of the National Astronomical Observatory of Japan (NAOJ) used two 28 cm amateur telescopes using the occultation technique in a 60-hour monitoring. The analysis of the data revealed what appears to be a planetesimal whose presence has long been predicted by the models of planetary formation but had never been identified.

A measurement of the Hubble constant based on quasars suggests possible changes to cosmological models

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An article published in the journal “Nature Astronomy” describes the use of quasars as cosmic tracers to measure the expansion of the universe up to 12 billion years ago. Guido Risaliti of the University of Florence and Elisabeta Lusso of Durham University studied the X-ray and optical emissions of a number of quasars using the comparison between those emissions to accurately assess their distances. The results could explain the discrepancies between the different measurements carried out with other methods suggesting that the density of the mysterious dark energy isn’t constant over time.

An explanation to the mystery of the stars surrounded by iron dust

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An article published in the journal “The Astophysical Journal Letters” reports the study of stars surrounded by iron dust in the Large Magellanic Cloud, one of the Milky Way’s satellite dwarf galaxies. A team of researchers led by Ester Marini, a doctoral student of the “Roma Tre” University, Rome, Italy, used data collected by NASA’s Spitzer Space Telescope to examine these stars that are in a phase of their life in which they lose their outer layers. Normally, that type of stars is surrounded by silicates and the anomaly is interesting because the dusts are important in the formation of new stars and planets as well.

Some details on the geology of Ultima Thule

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The Johns Hopkins University Applied Physics Laboratory, which collaborates with NASA at the New Horizons mission, has published a new image of the Kuiper Belt Object cataloged as 2014 MU69 and nicknamed Ultima Thule which offers more details of its geological features. Various pits, the great depression on the smallest lobe, the “collar” that joins the two lobes, clear and dark features will be studied to get answers to the many questions posed after receiving the first images taken by the space probe in its New Year’s Day 2019 flyby.

The planetary nebula ESO 577-24 seen in all its beauty by the Very Large Telescope

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ESO has published a new image of the planetary nebula ESO 577-24 captured by its Very Large Telescope (VLT) in Chile thanks to its FORS2 instrument, which for almost twenty years has been capturing some of the best astronomical images obtained by the VLT. ESO 577-24 represents the final phase of the life of the star at its center, cataloged as Abell 36, in astronomical terms an instant of agony since its duration is estimated around 10,000 Earth years.