Stars

Rho Cassiopeiae (Image courtesy Anugu et al. 2024)

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An article published in the journal “Astronomy & Astrophysics” reports the results of a study on some yellow hypergiants and in particular Rho Cassiopeiae, of which observations are available that go back to 1885. A team of researchers also examined observations of HR 8752, HR 5171A, and HD 179821 with a focus on the outbursts and the resulting variability that characterize yellow hypergiants. This study shows that the pulsations of Rho Cassiopeiae, or simply Rho Cas, become more intense when it approaches an explosive event. 138 years of observations have led to modeling Rho Cas’s behavior and predicting its future.

The RCW 38 cluster in infrared light (Image ESO/VVVX survey)

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ESO has released images of the stellar nursery cataloged as RCW 38, obtained using the VISTA InfraRed CAMera (VIRCAM) mounted on its Visible and Infrared Survey Telescope for Astronomy (VISTA) in Chile. It was obtained as part of the VISTA Variables in the Vía Láctea (VVV) astronomical survey, which produced the most detailed infrared map of the Milky Way. The infrared observations allow to see the electromagnetic emissions generated by young stars and protostars within RCW 38, which can pass through the blanket of gas and dust that blocks almost all other electromagnetic bands.

Artist's concept of a neutron star emitting a fast radio burst from its magnetosphere (Image courtesy Daniel Liévano, edited by MIT News)

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An article published in the journal “Nature” reports the identification of the origin of the fast radio burst cataloged as FRB 20221022A linking it to a magnetar-class neutron star, probably emerging from its magnetosphere. A team of researchers coordinated by MIT used observations conducted with the CHIME radio telescope to identify the origin of this already-known fast radio burst by exploiting the phenomenon of scintillation, comparable to how stars twinkle in the sky. This is further evidence of the link between magnetars and fast radio bursts, the very powerful emissions that can be one-time or repeated events.

The NGC 346 cluster with 10 circled stars surrounded by protoplanetary disks (Image NASA, ESA, CSA, STScI, O. C. Jones (UK ATC), G. De Marchi (ESTEC), M. Meixner (USRA))

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An article published in “The Astrophysical Journal” reports the results of the study of a group of protoplanetary disks with an age of up to 30 million years, even 10 times older than current models of planet formation predict. A team led by Guido De Marchi of ESA’s European Space Research and Technology Centre used observations conducted with the James Webb space telescope of the cluster NGC 346, in the Small Magellanic Cloud. That region is characterized by a limited amount of elements heavier than hydrogen and helium, just like the early universe. This study confirms that in those conditions, protoplanetary disks can last much longer than astronomers thought.

A group of galaxies observed by the James Webb Space Telescope (Image NASA, ESA, CSA)

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An article published in “The Astrophysical Journal” reports the results of a new measurement of the universe’s expansion rate obtained using observations conducted with the James Webb Space Telescope that confirms previous results obtained with Hubble. A team of researchers led by Adam Riess, who has been investigating the expansion of the universe for years, verified that the so-called Hubble tension, as the discrepancy between different measurements is called, was not due to limitations of the Hubble Space Telescope. According to Riess, this result confirms that our cosmological models are incomplete and there may be something we don’t yet understand about the universe.