--- title: "Astronomers May Have Discovered First-Ever “Black Neutron Star”" description: "A team of experts discovered an unusual celestial object that's 2.6 solar masses, too big to be a neutron star, too small to be a black hole." date: "2020-06-23" modified: "2020-06-23" authors: - name: "Victor Tangermann" job_title: "Senior Editor" link: "https://futurism.com/authors/victor" url: "https://futurism.com/astronomers-may-have-discovered-first-ever-black-neutron-star" categories: - "Science & Energy" tags: - "black hole" - "gravitational waves" - "LIGO" - "neutron star" --- # Astronomers May Have Discovered First-Ever “Black Neutron Star” ![A team of experts discovered an unusual celestial object that's 2.6 solar masses, too big to be a neutron star, too small to be a black hole.]() *\Image: Daniel Molybdenum\* If a star is gigantic enough, it can collapse in on itself to form a black hole. Stars that are still huge, but not big enough to become black holes, tend to explode in supernovae, eventually transforming into what is known as a neutron star. What has long puzzled scientists is that the smallest black holes tend to be [at least five times]() the mass of the Sun, while neutron stars are [at most]() 2.5 times the mass of the Sun. Inside those boundaries lies what has become known as the "mass gap" — a mysterious range between the mass of black holes and neutron stars. Now, though, a new discovery by a team of European astronomers seems to fit into that gap, suggesting a new class of objects that were thought to be impossible. Using the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO) in Louisiana and the Virgo detector in Italy, a team of experts discovered an unusual celestial object that's about 2.6 times the mass of the Sun. "The reason these findings are so exciting is because we’ve never detected an object with a mass that is firmly inside the theoretical mass gap between neutron stars and black holes before," Laura Nuttall, a gravitational wave expert from the University of Portsmouth's Institute of Cosmology and Gravitation, and co-author of [the paper]() published in *The Astrophysical Journal* today, said in [a statement]()*.* "Is it the lightest black hole or the heaviest neutron star we’ve ever seen?” The object — dubbed a "black neutron star" [by the ]()*[BBC]() —* was first detected in August, when it merged with a massive black hole of 23 solar masses, transforming into a final black hole of 25 solar masses some 800 million light-years from Earth. The two objects were extremely different in mass, making it an highly unusual merger. "It's a challenge for current theoretical models to form merging pairs of compact objects with such a large mass ratio in which the low-mass partner resides in the mass gap," Vicky Kalogera, professor at Northwestern University in the United States, and co-author, said in the statement. The mass ratio was so off, Kalogera likened it to "Pac-Man eating a little dot" and "in one bite." "This discovery implies these events occur much more often than we predicted, making this a really intriguing low-mass object," she added. But we still can't say for certain that we know what it actually is. "The mystery object may be a neutron star merging with a black hole, an exciting possibility expected theoretically but not yet confirmed observationally," Kalogera said. "However, at 2.6 times the mass of our sun, it exceeds modern predictions for the maximum mass of neutron stars, and may instead be the lightest black hole ever detected." **READ MORE:** ['Black neutron star' discovery baffles astronomers]() \[*BBC*\] **More on neutron stars:** *[Astronomers Watch Neutron Star “Charge Up" Before Huge X-Ray Blast]()* ## Author I've been at Futurism since 2017, where my role has evolved to encompass design, writing, and increasingly editing. I've always been fascinated by space exploration and advanced transportation, which I've leaned into by interviewing luminaries in those fields while closely following the dimensions of policy and regulation that allow next-generation projects to succeed -- or, sometimes, to fail. I'm also keenly interested in the effects of generative AI on society, policies, and democratic institutions, as well as clean energy, physics and biology, and the vagaries of tech leadership. My work for Futurism has been cited by publications including Ars Technica, Gizmodo, PC Magazine, Jalopnik, Fox News, and the New York Post. I spent my childhood living in locations including Manila, the Philippines, and Geneva, Switzerland, attended McGill University, and now live in Toronto, Canada. Before Futurism I worked at AskMen and a small photography studio. In my free time, I'm an avid gardener, foodie, and craft beer lover, as well as a maker of artisanal hot pepper sauces. I have a magnificent dog named Freida. ### Author social links [Bluesky]()