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London, November 30 (IANS): A unique stage in the evolution of the planetary system has been imaged by astronomers, showing fast-moving carbon monoxide gas flowing out of a star system over 400 light-years away.
They detected fast-moving carbon monoxide gas flowing away from a young, low-mass star – a unique stage in the evolution of the planetary system that can provide insight into how our solar system has evolved.
It suggests that how systems develop may be more complicated than previously thought.
“While it is not clear how the gas is ejected so quickly, we believe it could be produced by frozen comets vaporized in the star’s asteroid belt,” said the study authors from the University of Cambridge in the UK.
The detection was carried out with the Atacama Large Millimeter / submillimetre Array (ALMA) in Chile, as part of a survey of “class III” young stars reported in a previous paper.
Some of these Class III stars are surrounded by debris disks, which are believed to be formed by the continuous collisions of comets, asteroids and other solid objects, known as planetesimals, in the outermost reaches of newly formed planetary systems.
The residual dust and debris from these collisions absorb light from their central stars and radiate that energy again as a faint glow that can be studied with ALMA.
In the inner regions of planetary systems, planet-forming processes should result in the loss of all the hottest dust, and class IIII stars are the ones that are left with – at most – cold, faint dust.
These faint cold dust belts are similar to the known debris discs seen around other stars, similar to the Kuiper belt in our solar system, which is known to host much larger asteroids and comets.
In the survey, the star in question, ‘NO Lup’, which is about 70% of the mass of our sun, was found to have a faint, low-mass dusty disk, but it was the only Class III star in which the Carbon monoxide gas was detected, the first for this type of young stars with ALMA.
Although many young stars are known to still harbor the forming disks of the gas-rich planets they were born with, NO Lup is more evolved and could have been expected to have lost this primordial gas after its planets formed.
Although carbon monoxide detection is rare, what made the observation unique was the scale and velocity of the gas, which prompted a follow-up study to explore its motion and origins.
“The carbon monoxide detection alone was exciting, since no other young star of its kind had previously been photographed by ALMA,” said first author Joshua Lovell.
“But when we looked closer, we found something even more unusual: given how far the gas was from the star, it was moving much faster than expected. This puzzled us for quite some time,” he added. Lovell.
Further analysis also showed that gas can be produced during asteroid collisions, or during periods of sublimation – the transition from a solid to a gas phase – on the surface of the star’s comets, which are supposed to be rich in carbon monoxide.
The results were to be presented at the “Five Years After HLTau” virtual conference in December.
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