NASA's James Webb Space Telescope (JWST) has revealed a fascinating phenomenon after it captured an image of a star located around 5,600 light-years away in detail. The image from the telescope depicts the star surrounded by what researchers suspect are concentric circles of light radiating outward. The star, in the image, is a binary pair of rare stars in the constellation of Cygnus. The interaction between them results in periodic eruptions of dust that are expanding out in shells into the space around the stars over time.
The shells of dust glow in infrared allow NASA's JWST sensitive Mid-Infrared Instrument (MIRI) to capture it in detail, according to a report by Science Alert. The pair of rare stars, known as a colliding wind binary, consists of an extremely rare Wolf-Rayet star called WR 140 and a hot and massive O-type star companion, which is also a rare object. Wolf-Rayet stars are described as hot, old, and luminous at the end of their main-sequence lifespan. They are losing mass at a high rate and are rich in nitrogen and carbon, but lack hydrogen.
The O-type stars, meanwhile, are considered to be among the most massive stars known that are bright and hot. Their lifespan, however, is quite brief due to their gigantic size. The pair of stars in WR 140 have fast stellar winds that are blowing out into space at a speed of roughly 3,000 kilometers per second. Due to this, both the stars are losing mass at a high rate.
The dust, in the system, is in the form of carbon that absorbs ultraviolet light from the stars. This heats up the dust which re-emits thermal radiation that has been captured in Webb's image. The stellar winds blow the wind outward which expands the partial dust shells. The shells expand and cool while being blown out and lose heat and density in the process.
The orbit of the binary star has a 7.94-year period and due to this the wind collision and dust production take place every 7.94 years. This implies that one can count the rings of the nebula around the binary to determine the outermost visible dust shell's age. In the image, 20 such rings are visible which means 160 years' worth of dust shells are visible.
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