Stars

HBC 672 seen by Hubble (Image NASA, ESA, and STScI)

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An article published in “The Astrophysical Journal” reports multi-epoch observations conducted with the Hubble Space Telescope of the star HBC 672 and the movement of the shadow projected by its protoplanetary disk onto an interstellar cloud. A team of researchers led by Klaus Pontoppidan of the Space Telescope Science Institute (STScI) compared the positions of the shadow over 13 months, noting its movement, which has a visual effect similar to a flapping of wings as its shape reminds of that to the point that the star and its protoplanetary disk have been nicknamed Bat Shadow. It could be a planet that is forming and warping the disk.

Artist's concept of the GW190814 event

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An article published in “The Astrophysical Journal Letters” reports a study on the origin of gravitational waves detected in the event cataloged as GW190814 on August 14, 2019, in which a black hole with a mass about 23 times the Sun’s merged with an object with a mass about 2.6 times the Sun’s whose nature is uncertain. The scientists of the LIGO and Virgo collaborations analyzed the data collected by the network of interferometers that recorded the gravitational waves emitted by that event. The problem is that the mass of the less massive object is within a gap where it’s not currently possible to say whether a compact object is a neutron star or a black hole.

The sky seen at X-rays by eROSITA

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The Max Planck Institute for Extraterrestrial Physics (MPE) has published an X-ray universe map obtained thanks to the eROSITA instrument, which the institute built for the Spektr-RG space telescope. This map includes about a million objects related to the hot and energetic part of the universe. It’s about 4 times deeper than the previous map of this type and contains about 10 times the number of energy sources, the equivalent of those discovered by all X-ray telescopes combined in over half a century of observations. It took about six months for eROSITA to complete this survey, which is only the first of eight expected in the course of about four years that will offer information that is likely to be used for decades.

NGC 6302 seen by Hubble (Image NASA, ESA, and J. Kastner (RIT))

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An article in the journal “Galaxies” reports a study of the planetary nebulae NGC 6302, also known as the Butterfly Nebula for its shape, and NGC 7027. A team of researchers used the Hubble Space Telescope in multiple wavelength observations to offer the most complete views ever obtained of these two planetary nebulae. Both of them were already studied with Hubble and many other instruments in the past, but the Wide Field Camera 3 instrument allowed to obtain more details that mean more scientific information on the processes in progress and even more spectacular images.

Swift J1818.0-1607 observed by XMM-Newton (Image courtesy ESA/XMM-Newton; P. Esposito et al. (2020))

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An article published in “The Astrophysical Journal Letters” reports a study on Swift J1818.0-1607, the youngest pulsar discovered so far, which offers evidence that it’s at the same time a magnetar and one of the very few to also have radio emissions. A team of researchers have used ESA’s XMM-Newton, NASA’s Swift and NuSTAR space telescopes to detect X-ray emissions, and the Sardinia Radio Telescope to detect radio emissions in a complex observation campaign necessary to study the combined characteristics of the two types of neutron star.