Stars

CK Vul

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An article published in the journal “Nature Astronomy” describes the discovery of aluminum monofluoride (AlF) molecules containing aluminum-26, a radioactive isotope of this element, in interstellar space. A team of astronomers used the ALMA and NOEMA radio telescopes to trace its origins to the variable star CK Vulpeculae (CK Vul), the remnant of the merger between two stars observed from the Earth between 1670 and 1672 and called Nova Vulpecola 1670. It’s the first observation of aluminum-26 that leads to the identification of its origin, which occurred in a very rare event.

Artist's impression of Sagittarius A* and S2

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An article published in the journal “Astronomy & Astrophysics” describes a verification of a phenomenon predicted by Albert Einstein’s general theory of relativity. Scientists from the GRAVITY collaboration used observations conducted with ESO’s Very Large Telescope (VLT) in Chile to observe the effects of the motion of a star called S2 as it passes through the extreme gravitational field near the supermassive black hole at the center of the Milky Way.

Scheme of Hubble and Gaia at work (Image NASA, ESA, and A. Feild (STScI))

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An article published in the journal “The Astrophysical Journal” describes a new measurement of the expansion of the universe. A team of astronomers led by Nobel Prize winner Adam Riess combined observations made with the Hubble Space Telescope and those made with ESA’s Gaia space probe, an observatory that specifically aims to map billions of objects in the sky including the variable stars called Cepheid variable used for those measurements. The new results increase the accuracy but also the discrepancy between the measures of the expansion of the near universe and those of the early universe.

Artist's impressione of the Milky Way and the Sausage dwarf galaxy (Image courtesy V. Belokurov (Cambridge, UK); Based on image by ESO/Juan Carlos Muñoz)

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A series of articles published in the journals “Monthly Notices of the Royal Astronomical Society” and “The Astrophysical Journal Letters” or on the arXiv website describe various aspects of a study on the consequences of the merger of the Milky Way and a dwarf galaxy nicknamed Sausage. A team of astronomers used data collected by ESA’s Gaia space probe to reconstruct that event from 8-10 billion years ago that profoundly influenced the Milky Way.

The Eta Carinae system (Image NASA, ESA, and the Hubble SM4 ERO Team)

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An article published in the journal “Nature Astronomy” describes a research on the Eta Carinae system, which consists of two giant blue stars with an overall brightness millions of times the Sun’s. A team led by astrophysicist Kenji Hamaguchi of NASA’s Goddard Space Flight Center used observations carried out with the NuSTAR telescope between March 2014 and June 2016 and other space telescopes to conclude that the two stars are probably accelerating very high energy particles and that some will reach the Earth in the form of cosmic rays.