Astronomy / Astrophysics

The runaway star Zeta Ophiuchi and its bow shock

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An article accepted for publication in the journal “Astronomy and Astrophysics” reports a study on the star Zeta Ophiuchi, a so-called runaway star that became famous even beyond the field of astronomy for its bow shock, the enormous shock wave similar to the waves generated in the water by the bow of a ship. A team of researchers led by Samuel Green from the Institute for Advanced Studies in Dublin, Ireland, built detailed computer models of the bow shock to try to explain the observed data. The results confirm the origins of Zeta Ophiuchi but only partially explain the X-ray emissions detected.

Artistic concept of gravitationally bound binary systems (Image NASA/JPL-Caltech/UCLA)

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An article published in the journal “Monthly Notices of the Royal Astronomical Society Letters” offers a number of clues about the triple system TIC 470710327 being the result of a stellar merger. A team of researchers used the HERMES spectrograph mounted on the Mercator Telescope for follow-up observations of this system, which was discovered thanks to NASA’s TESS space telescope, a discovery that was announced in an article published in April 2022 in the journal “Monthly Notices of the Royal Astronomical Society”. Computer simulations led the researchers to conclude that originally there were two gravitationally-bound binary systems and in one of them, the two stars merged into one that ended up forming a triple system with the other two.

Artist's representation of the VFTS 243 system

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An article published in the journal “Nature Astronomy” reports the discovery of a probable dormant black hole in the Large Magellanic Cloud, one of the dwarf galaxies satellite of the Milky Way. A team of researchers spotted it in the VFTS 243 system after a thorough examination of a binary system located in the Tarantula Nebula in which a candidate was identified to be tested in the search for black holes. Six years of observations conducted with ESO’s VLT allowed to rule out other possible explanations for the nature of the objects studied. An interesting conclusion is that the black hole discovered is the result of a collapse of the parent star that occurred without a supernova.

Webb's First Deep Field (Image NASA, ESA, CSA, and STScI)

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NASA has released the first official images captured by the James Webb Space Telescope. The presentation was made in collaboration with ESA and CSA (Canadian Space Agency), the other space agencies that work together with NASA on the project and its management. Yesterday, when it was afternoon at the White House, US President Joe Biden personally presented the top image, Webb’s First Deep Field image that includes the SMACS 0723 galaxy cluster as a preview, a proof of the importance of this space telescope.

16 stars of the S cluster

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An article published in “The Astrophysical Journal” reports the identification of the star with the closest orbit around Sagittarius A*, the supermassive black hole at the center of the Milky Way. A team of researchers cataloged it as S4716 after finding it in data collected over twenty years with the Keck Observatory, the VLT, and the VLTI. The star S4716 completes an orbit in about 4 Earth years and its distance from Sagittarius A* is as close as 100 times the Earth’s from the Sun. Its discovery, which breaks the record of the star S4711, is surprising and will help to better understand how stars in that area formed and moved, as it’s difficult to think that it formed this close to a supermassive black hole.