Astronomy

For the first time, astronomers have confirmed the existence of a lone black hole — one with no star orbiting it.

It’s “the only one so far,” says Kailash Sahu, an astronomer at the Space Telescope Science Institute in Baltimore.

In 2022, Sahu and his colleagues discovered the dark object coursing through the constellation Sagittarius. A second team disputed the claim, saying the body might instead be a neutron star. New observations from the Hubble Space Telescope now confirm that the object’s mass is so large that it must be a black hole, Sahu’s team reports in the April 20 Astrophysical Journal. More

The decades-long mystery of a never-ending explosion of X-rays around the remains of a dead star may have finally been solved. The radiation probably originates from the scorching-hot wreckage left behind by a giant planet’s annihilation.

This discovery stems from four decades of X-ray observations of the Helix Nebula, located 650 light-years from Earth. The stream of X-ray radiation remained effectively constant over at least 20 years, researchers report in the January Monthly Notices of the Royal Astronomical Society. The best explanation, the scientists say, is that the ruins of a Jupiter-sized world continuously fall onto the nebula’s white dwarf star, getting frazzled and glowing in X-rays. More

The black hole at the Milky Way’s heart neither slumbers nor sleeps. Instead, the ring of plasma surrounding it flickers constantly, punctuated by superbright flares, observations show.

Astronomers used the James Webb Space Telescope to observe Sgr A* and its disk for hours at a time over the course of a year, from April 2023 through April 2024. These were the longest continuous observations yet of our galaxy’s central supermassive black hole.

The telescope revealed a “constant bubbling” in the disk’s light that changed every few seconds or minutes, says astrophysicist Farhad Yusef-Zadeh of Northwestern University in Evanston, Ill. A few times a day, and seemingly at random, the disk would emit a blindingly bright flare, Yusef-Zadeh and colleagues report in the Feb. 20 Astrophysical Journal Letters. More

In January in Monterrey, Mexico, Iván Venzor was one of only a dozen people in the world to glimpse a potential Jupiter-sized planet crossing in front of a distant star.

It happened too fast to see by eye — just a seconds-long flicker of light — but Venzor’s backyard telescope recorded the data, allowing him to verify the event with researchers. “I’m having dinner with my family, and I’m trying to discover a new kind of planet from a few meters outside,” says Venzor, a hobby astronomer. “It’s effortless.” More

The first generation of stars in the universe could have produced significant amounts of water upon their deaths, just 100 million to 200 million years after the Big Bang.

Signatures of water have previously been observed some 780 million years after the Big Bang. But now, computer simulations suggest that this essential condition for life existed far earlier than astronomers thought, researchers report March 3 in Nature Astronomy.

“The surprise was that the ingredients for life were all in place in dense cloud cores [leftover after stellar deaths] so early after the Big Bang,” says astrophysicist Daniel Whalen of the University of Portsmouth in England. More

Alpha Centauri, the nearest star system to the sun, is probably shedding comets and asteroids into our solar system — and even producing a few meteors in our sky.

Located just 4.3 light-years from Earth, Alpha Centauri consists of three stars that revolve around one another. If Alpha Centauri has an Oort cloud of distant comets as the sun does, about a million of these objects larger than a football field are now in our solar system, astronomers Cole Gregg and Paul Wiegert of the University of Western Ontario in London, Canada, estimate in work submitted February 5 to arXiv.org. More

A staccato blast of electromagnetic energy has been tracked to an old, dead galaxy for the first time. The discovery supports the idea that there are more ways to produce such flares, called fast radio bursts, than originally thought.

Fast radio bursts, or FRBs, are millisecond-long eruptions of intense radio waves. Astronomers have observed thousands of these blasts, but only about 100 have been traced back to their origins, says astronomer Tarraneh Eftekhari of Northwestern University in Evanston, Ill. Almost all of them came from lively neighborhoods full of young stars. More

NATIONAL HARBOR, MD. — A bright blip in a distant galaxy may link two mysterious categories of cosmic flares. The event, which astronomers playfully call the Platypus, could also offer a new way to understand the origins of supermassive black holes that reside at the centers of most galaxies.

The brilliant burst, spotted in a dwarf galaxy about 6.5 billion light-years from Earth, has many of the hallmarks of a tidal disruption event, the final flash of a star being ripped apart by a black hole. But it also resembles another type of flash, dubbed an LFBOT, which astronomers think might be a class of exploding star. More