A dead star dances with a dying giant, and the flashes finally make sense

Somewhere in the constellation Centaurus, about 13,000 light-years from Earth, a dead star is caught in a strange and violent dance with its dying partner. The neutron star—a city-sized remnant with the mass of our sun packed into a sphere roughly 12 miles across—spins through space, sending a wobbling beam of X-rays toward us like a lighthouse that never quite keeps time. It is, astronomers say, a zombie: undead, ultradense, and emitting flashes that have puzzled scientists for years. Now, with the help of a new X-ray telescope, researchers have finally glimpsed what drives those flashes—a colossal plume of stellar wind, so concentrated and energetic that scientists have described it with a word more often used in less dignified contexts.

The binary system is known as BP Crucis. It pairs a blue hypergiant star called Wray 977—roughly 60 times larger than the sun—with the neutron star GX 301-2 . The neutron star completes an orbit every 41.5 days, and it experiences intense X-ray flares when it reaches its closest and farthest points from its partner . For decades, researchers suspected those flares were triggered by the neutron star passing through a stream of material blown off the hypergiant. But they had no way to prove it.

That proof came from the X-ray Imaging and Spectroscopy Mission, or XRISM, a space telescope jointly operated by NASA and the Japan Aerospace Exploration Agency. During a 16-hour observation period coinciding with one of the neutron star's flares, XRISM captured highly detailed X-ray spectra showing how a dense stream of plasma acted very close to the neutron star . The data revealed "rapidly changing emission and absorption lines," allowing researchers to simulate exactly how the plasma fell onto and swirled around the passing star .

The culprit is the hypergiant's stellar wind—a single, concentrated plume of ionized gas ejected at roughly 335,000 miles per hour . Scientists believe the plume is shaped into a narrow stream by the gravitational influence of the neutron star itself . When GX 301-2 passes through this plume, material accumulates on its surface. When enough has gathered, the star releases a burst of energy—an X-ray flare bright enough to be detected from Earth.

"This is the first time that researchers have ever detected this type of stellar material interacting with a neutron star, or with any other similar stellar remnant," the study notes . Study co-author Nazma Islam described the observations as "groundbreaking," adding that the clarity of the data meant the analysis had to be especially detailed . The findings were published September 18 in the journal Science Advances.

Astronomers believe BP Crucis offers a unique laboratory for understanding how compact objects interact with the extreme winds of massive stars. The team hopes to use XRISM to observe future flares, building a more complete picture of this peculiar cosmic relationship .

New observations with the XRISM space telescope have revealed that a neutron star in the BP Crucis system flares when it passes through a concentrated plume of stellar wind from its hypergiant companion. The findings, published in Science Advances, mark the first time this type of interaction has been directly detected.

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Sources: Live Science, Yahoo News, Science Advances, NASA Goddard Space Flight Center, University of Maryland Baltimore County