Astro Blog

By Daniel Clery , Science.  Excerpt: Astronomers studying the murky center of our Milky Way Galaxy have discovered something they never expected:  a pair of young stars orbiting each other near the supermassive black hole that is our Galaxy’s dark heart . The observation—reported today in Nature Communications—comes as a surprise because astrophysicists had thought the black hole’s intense gravity would either rip the stars in such a pair apart or squash them together. But the new object, dubbed D9, shows that such a “binary” can survive, at least briefly, near the black hole, and it could help explain other mysterious objects in the vicinity. ...For many years, two teams, in California and Germany, monitored the  closest of those stars . About 20 years ago, both proved the star’s eccentric, high-speed orbit could only arise if it was circling a compact object with extreme mass—a black hole. For that work, the teams’ leaders, Reinhard Genzel of the Max Planck Institu...

By Valeriy Vasilyev et al, Science.  Editor's Summary: Solar flares are bright, transient, multiwavelength emissions from active regions on the Sun. The most intense directly observed solar flares release energies of about 10 32  erg. It is unclear whether the Sun can produce more intense flares than that or how often they might occur. Vasilyev  et al . investigated brightness measurements of 56,000 Sun-like stars observed by the Kepler space telescope. They identified almost 3000 bright stellar flares with energies of about 10 34  to 10 35  erg, which are called superflares. The occurrence rate is about one superflare per star per century. If the Sun behaves like the stars in this sample, then it could produce superflares at a similar rate. —Keith T. Smith.  Full article at https://www.science.org/doi/10.1126/science.adl5441 .