BYLINE: Megan Watzke
Individuals typically take into consideration archaeology taking place deep in jungles or inside historic pyramids. Nonetheless, a crew of astronomers has proven that they’ll use stars and the stays they go away behind to conduct a particular form of archaeology in area.
Mining information from NASA’s Chandra X-ray Observatory, the crew of astronomers studied the relics that one star left behind after it exploded. This “supernova archaeology” uncovered essential clues a couple of star that self-destructed – in all probability greater than 1,000,000 years in the past.
At the moment, the system known as GRO J1655-40 comprises a black gap with almost seven instances the mass of the Solar and a star with about half as a lot mass. Nonetheless, this was not at all times the case.
Initially GRO J1655-40 had two shining stars. The extra large of the 2 stars, nonetheless, burned by way of all of its nuclear gasoline after which exploded in what astronomers name a supernova. The particles from the destroyed star then rained onto the companion star in orbit round it, as proven within the artist’s idea.
With its outer layers expelled, together with some putting its neighbor, the remainder of the exploded star collapsed onto itself and shaped the black gap that exists at this time. The separation between the black gap and its companion would have shrunk over time due to power being misplaced from the system, primarily by way of the manufacturing of gravitational waves. When the separation grew to become sufficiently small, the black gap, with its robust gravitational pull, started pulling matter from its companion, wrenching again a few of the materials its exploded dad or mum star initially deposited.
Whereas most of this materials sank into the black gap, a small quantity of it fell right into a disk that orbits across the black gap. By means of the consequences of highly effective magnetic fields and friction within the disk, materials is being despatched out into interstellar area within the type of highly effective winds.
That is the place the X-ray archaeological hunt enters the story. Astronomers used Chandra to look at the GRO J1655-40 system in 2005 when it was significantly brilliant in X-rays. Chandra detected signatures of particular person components discovered within the black gap’s winds by getting detailed spectra – giving X-ray brightness at completely different wavelengths – embedded within the X-ray gentle. A few of these components are highlighted within the spectrum proven within the inset.
The crew of astronomers digging by way of the Chandra information had been in a position to reconstruct key bodily traits of the star that exploded from the clues imprinted within the X-ray gentle by evaluating the spectra with pc fashions of stars that explode as supernovae. They found that, based mostly on the quantities of 18 completely different components within the wind, the long-gone star destroyed within the supernova was about 25 instances the mass of the Solar, and was a lot richer in components heavier than helium as compared with the Solar.
This evaluation paves the best way for extra supernova archaeology research utilizing different outbursts of double star methods.
A paper describing these results titled “Supernova Archaeology with X-Ray Binary Winds: The Case of GRO J1655−40” was printed in The Astrophysical Journal in Might 2024. The authors of this research are Noa Keshet (Technion – Israel Institute of Expertise), Ehud Behar (Technion), and Timothy Kallman (NASA’s Goddard Area Flight Middle).
NASA’s Marshall Area Flight Middle in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Middle controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
