Category: mass gap

Ask Ethan: Did We Just Find The Universe’s Missing Black Holes?

“As interesting as this new black hole is, and it really is most likely a black hole, it cannot tell us whether there’s a mass gap, a mass dip, or a straightforward distribution of masses arising from supernova events. About 50% of all the stars ever discovered exist as part of a multi-star system, with approximately 15% in bound systems containing 3-to-6 stars. Since the multi-star systems we see often have stellar masses similar to one another, there’s nothing ruling out that this newfound black hole didn’t have its origin from a long-ago kilonova event of its own.

So the object itself? It’s almost certainly a black hole, and it very likely has a mass that puts it squarely in a range where at most one other black hole is known to exist. But is the mass gap a real gap, or just a range where our data is deficient? That will take more data, more systems, and more black holes (and neutron stars) of all masses before we can give a meaningful answer.”

Last week, an incredible new story came out: scientists discovered a massive object some 10,000 light-years away that emits no light of its own. From the giant star in orbit around it, we were able to infer its mass to a well-constrained range, with the mean value hovering right at 3.3 solar masses.The lack of X-rays from it, based on the field strength associated with neutron stars and the orbit of the giant star itself, very strongly indicates that this object is not a neutron star, but a black hole.

Does this mean we’ve discovered a black hole in the so-called “mass gap” range? Yes! But does it disprove the existence of a mass gap overall? Not so much. Come get the full story on this edition of Ask Ethan!