Astronomy / Astrophysics

A catalog of gravitational wave detections includes 4 new events

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.

Asteroid Bennu (Image NASA/Goddard/University of Arizona)

NASA and Lockheed Martin have confirmed that the OSIRIS-REx space probe has reached the asteroid Bennu. From its orbit, at a distance of about 5 kilometers (a bit more than 3 miles), it will start studying its surface creating a map over the course of about a year and a half. This will allow NASA scientists not only to get to know it better but also to choose the most suitable area to proceed with the next phase of the mission, which will consist of taking samples from Bennu’s surface to be returned to Earth.

The quasar 3C 273 (Image ESA/Hubble & NASA)

An article published in the journal “Nature” describes the first detailed observation of the environment surrounding a supermassive black hole outside the Milky Way. A team of astronomers led by Professor Hagai Netzer of the Tel Aviv University used the GRAVITY instrument installed on ESO’s VLTI to examine the first quasar discovered, known as 3C 273, uncovering gas clouds that move quickly around the black hole that powers that quasar and forms its heart.

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

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.

The Nili Fossae (Image ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO)

ESA has published new photos of the region on planet Mars called Nili Fossae taken by its Mars Express space probe’s High Resolution Stereo Camera (HRSC). The Nili Fossae are a group of tectonic depressions called graben that show signs not only of geological activity but also of erosion by winds and especially by water that dug the shapes still visible today.