Chinese Academy of Sciences
The Einstein Probe captured the X -ray flash of a very dodge celestial pair, a large hot star, 12 times larger than our sun.
A Einstein Probe, a satellite with “Lobster Eyes”, captured the x -ray flash of a very dodge celestial pair. The discovery opens a new way to explore the way massive stars interact and evolve, confirming the unique power of the mission to discover ephemeral sources of x -ray in the sky.
The strange celestial pair consists of a Great hot star, more than 10 times larger than our sunand one Little white dwarf compact, with a mass similar to that of our star. To date, only some of these systems were found. And it was the first time that scientists could follow the X -rays from such a curious pair, from their sudden initial outbreak to their disappearance.
On May 27, 2024, the Wide-Field X-Ray Telescope) of the Einstein Probe detected X-ray from our neighboring galaxy, the small cloud of Magalhães (PNM). To find out the origin of this new celestial sign, designated by EP J0052, scientists pointed to Einstein Probe’s FXT-up (FXT-up) in this direction.
WXT also triggered NASA’s X-ray and Nicer telescopes to point to the newly discovered object. ESA’s XMM-Newton followed 18 days after this activation.
“We were chasing ephemeral sources when we came across this new X -ray point in PNM. We realize thatAnd we were looking at something unusualthat only Einstein Probe could capture ”, Alessio Marino, a postdoctoral researcher at ICE-CSIC (Institute of Spatiales-Superior Consejo of Scientific Research) in Spain, and the main author of the new study.
“This is because, among the current telescopes that monitor x -ray sky, the WXT is the only one that can see low energy X -rays with sufficient sensitivity to capture the new source.”
Initially, scientists thought that EP J0052 could be a well -known type of binary system that shines in X -rays. They are pairs made up of a neutron star that devours the material of a massive companion star. However, there was something in the data that told a Different story …
A rare discovery
Thanks to the fact that Einstein Probe has captured the new source since its initial outbreak, scientists were able to analyze data lots from different instruments. Examined the way light varied along a range of x -ray wavelengths for six days, and discovered some of the elements present in the explosion material, such as the nitrogen, oxygen and neon. The analysis provided crucial clues.
“We quickly understand that we were facing a rare discovery of a very dodge celestial couple“Explains Alessio. “The unusual duo consists of a massive star we call star Be, With a mass 12 times higher than the sun, and a stellar ‘corpse’ known as a white dwarf, a compact and hyperdenso object, with a mass similar to that of our star. ”
As two stars orbit to each other and the intense gravitational field of the white dwarf pulls the subject of his companion. As more and more material (mainly hydrogen) “it rains” over the compact object, its strong gravitation compresses it, until an uncontrolled nuclear explosion begins. This creates a flash of bright light on a wide range of wavelengths, from visible, passing through ultraviolet and x -rays.
At first glance, the existence of this pair is intriguing. The Ba mass stars quickly burn their nuclear fuel reserve. Their lives are intense and short, lasting about 20 million years. Your mate is (usually) the collapsed remnant of a star similar to our sun that would live for several thousand years of years.
Since binary stars form typically together, as is the Star supposedly with short life is still shiningwhile the alleged Happy Life Star has died?
There is an explanation.
A two -star story
Scientists think that the couple started togetherlike a better combined binary pair, consisting of two very large stars, six and eight times more massive than our sun.
The largest star sold out its nuclear fuel earlier and began to expand, releasing matter to your mate. First, the gas in its swollen outer layers was pulled by the companion; Then its remaining outer layers were ejected, forming a wrapper around the two stars, which later became a disc and finally dissolved.
At the end of this drama, the companion star had grown until the sun’s mass was reached, while the other’s core core had collapsed to become a white dwarf with just over one solar mass. Now, it’s the turn of the white dwarf steal and devour the material From the outer layers of star Be.
“This study gives us new information about a rarely observed phase of star evolution, which is the result of a complex material exchange which must have happened between the two stars, ”comments Ashley Chrimes, a researcher and x -ray astronomer at ESA. “It’s fascinating to see how a pair of massive stars in interaction can produce such an intriguing result.”
The monitoring observation of ESA’s XMM-Newton Mission towards EP J0052, 18 days after the first observation of Einstein Probe, did not see the signal. This fact establishes a Limit for the Duration of the Outbreakshowing that it was relatively brief.
The duration of the short explosion and the presence of neon and oxygen point to a somewhat massive white dwarf type, probably 20% more massive than the sun. Its mass is close to the so -called limit of Chandrasekhar, Above which the star would continue to implode, becoming an even denser neutrons star, or exploding as supernova.
“The explosions on pairs consisting of a white dwarf and a Be star have been extraordinarily difficult to detect as they are better observed in low energy X -rays. The advent of Einstein Probe provides the unique opportunity to detect these ephemeral sources and to test our understanding of how massive stars evolve, ”comments Erik Kuulkers, ESSTein Project Scientist from ESA.
“This discovery shows the revolutionary abilities of this mission.”
