Astronomy

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

The Milky Way keeps its planets close to its chest. Stars in a thin, flat disk bisecting the galaxy have more planets on average than stars in a thicker, enveloping disk — and astronomers now think they know why.

Stars that currently live in the galaxy’s thick disk were born during a time of galactic chaos, says MIT astrophysicist Tim Hallatt. The stars’ violent upbringing hindered their ability to grow and retain planets, he and astrophysicist Eve Lee, formerly of McGill University in Montreal, report January 22 in the Astrophysical Journal. More

BOSTON — For the first time, astronomers have detected an astrosphere around a star like the sun.

This bubble of hot gas is blown by a star’s stellar wind, a constant stream of charged particles every star emits. The sun’s version of this bubble, called the heliosphere, marks the edge of our solar system and protects the planets from most of the high-energy cosmic rays that zip about the galaxy (SN: 12/10/18, SN: 10/15/09).

Astronomers have seen analogous bubbles around hot stars, dying stars and baby stars — but not sunlike stars. More