Stars

A catalog of gravitational wave detections includes 4 new events

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Two articles published on the arXiv server show a catalog of gravitational wave events detected by the LIGO and Virgo collaborations and the inferred properties concerning the black hole pairs discovered in the mergers. So far, 7 events were announced but the analysis of the data led to the discovery of 4 more events of which one was detected by Virgo as well. Of the 11 now known, there’s the one that became famous because it was generated by two neutron stars that led to a kilonova while the other 10 were generated by black hole pairs.

The V4046 Sgr system (Image V. D’Orazi/Sphere/Inaf)

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An article published in the journal “Nature Astronomy” describes a study of the V4046 Sagittarii, or simply V4046 Sgr, binary system. A team of researchers led by Valentina D’Orazi of INAF, Padua, Italy, used the SPHERE instrument on ESO’s Very Large Telescope (VLT) to examine the rotating shadows projected on the protoplanetary disk that orbits the two young stars. The mapping of the shadows’ movements made it possible to better understand that system’s characteristics thanks to the motion of the two stars, which orbit each other in almost 2.5 days.

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An article published in the journal “The Astrophysical Journal” describes a new research on the possible climate existing on the seven rocky planets of the star TRAPPIST-1’s system. A team of astronomers coordinated by the University of Washington (UW) used updated climate models to try to understand what kind of atmospheres they can have as a result of environmental evolution based on the observations collected. The result is that the planet TRAPPIST-1 e is the one most likely to have liquid water on its surface.

The star HD 186302 at the center (Image courtesy CDS Portal/Simbad)

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An article published in the journal “Astronomy & Astrophysics” describes the discovery of a twin star of the Sun. It’s HD 186302, studied by a team of researchers led by Vardan Adibekyan of the Instituto de Astrofísica and Ciências do Espaço (IA), in Portugal, starting from the data collected by the AMBRE project that collected about 230,000 star spectra, along with other data collected by ESA’s Gaia space probe. HD 186302 is really similar to the Sun not only as an age and chemical composition but also in mass and size and this offers hopes that it has planets similar to the Earth.

Artist's concept of Barnard's Star and its planet Barnard’s Star b (Image ESO/M. Kornmesser)

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An article (link to PDF file) published in the journal “Nature” describes the discovery of a possible super-Earth orbiting the Barnard’s Star, a red dwarf that in astronomical terms is in the neighborhood being about 6 light years away from the Earth. The Red Dots and CARMENES projects led to the discovery of what was named Barnard’s Star b and could be the second exoplanet closest to the solar system after Proxima b.