At the Astrobytes blog (https://astrobites.org/2019/02/19/the-search-for-black-hole-teenagers/ … we have a population of indeterminate black holes (low luminoscity) under discussion. Most galaxies seem to contain a super massive black hole at their centre but how did they grow into such a grand phenomenon as there is a distinct shortage of baby black holes – and even teenager black holes. Cosmologists think less massive black holes can form when a star collapses in upon itself. Various theories have endured. One of these is that the earliest stars left behind small baby black holes which over time merged together to form ever bigger black holes – a sort of accretion process. They have not been seen but are probably too small in any case. However, if this was the case we'd expect to see some teenager type black holes – but we can't. The authors of the study found the accretion of matter from a hot galaxy is not enough to explain the growth of starter new black holes so they must come from mergers of smaller black holes. Are they lost down a blind alley?
At https://phys.org/print469632431.html … first evidence discovered of a giant remnant around an exploding star. This concerns why and how supernovas explode. Research suggests some stars have been erupting for a very long time – and some erupt more frequently than others. Frequent eruptions resulted in a 'super remnant' surrounding a nova event, we are told.
At https://phys.org/print469633396.html …. sources of meteorites. This time the source is thought to be the asteroid belt – originating from colliding asteroids (and fragmenting asteroids).