An article published in “The Astrophysical Journal Letters” reports the discovery that the system cataloged as LP 413-53AB consists of two ultracool dwarf stars that orbit each other in just 17 hours. A team of researchers led by Chih-Chun “Dino” Hsu of Northwestern University used observations conducted with the Keck Observatory telescopes to resolve two stars so small and so close. Previously, three binary systems composed of ultracool dwarfs had been discovered but they were young stars in astronomical terms while the pair of LP 413-53AB is estimated to be some billion years old. We don’t know how difficult these pairs are to find due to their weak emissions, and explaining the existence of LP 413-53AB is difficult.

An article to be published in “The Astrophysical Journal” reports a study on Tycho supernova remnants which offers new information on the geometry of its magnetic fields. A team of astronomers led by Riccardo Ferrazzoli of the Italian National Institute of Astrophysics used observations conducted with the IXPE space telescope to examine the polarized X-rays emitted by these supernova remnants. This allowed new clues to be found about the conditions in the shock waves generated by the supernova that accelerate particles to speeds close to the speed of light.