It’s only the second time that astronomers have discovered such a bubble related to the “outflow” of material from a developing star
Scientists have discovered a mysterious new “molecular bubble” in space, located approximately 10,000 light-years away from Earth. The discovery was made using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, one of the most advanced telescopes in the world.
The molecular bubble, which is approximately 100 light-years in diameter, appears to be composed of a large concentration of gas and dust. Scientists believe that the bubble was formed by the explosion of a massive star, which sent shockwaves through the surrounding interstellar medium, causing the gas and dust to condense into the bubble shape.
This discovery is significant because it provides new insights into how massive stars can impact their surrounding environment and shape the evolution of the interstellar medium. The molecular bubble is also believed to contain the building blocks for new stars and planetary systems, making it an important target for future study.
The discovery of this new molecular bubble is a testament to the incredible advancements made in astronomy and astrophysics in recent years. Scientists will continue to study the bubble to learn more about its properties and what it can reveal about the early stages of star and planet formation.
Chaotic and complex
Star creation is a chaotic and complex process. A dense, chilly cloud made up of tiny dust grains and gases, including hydrogen, is where it all begins.
A chunk of this cloud eventually dissipates in a swirl under the force of its own gravity, absorbing more particles from the surrounding material. Once it has amassed sufficient mass, the resultant pressure and heat produce the hydrogen that gives stars their core.
However, when a young star gathers mass, it lashes out at the area around it. Not all of the material enters the star, some is accelerated along the magnetic field lines of the protostar towards the poles, where it bursts into space as astrophysical jets. Protostars also generate winds that create vast gaps in the cloud from which they emerge.
These outflows are named “feedback”, which are thought to be crucial in both stopping protostellar growth and the development of the interstellar medium, the gas and dust that floats around in the voids between stars.
Because molecular clouds are so dense, it is difficult to detect what is happening inside of them when a star forms. Longer wavelengths of light can pass through the cloud, but shorter ones cannot.
The nebula known as Barnard 18 is dark and neither emits nor reflects light. Optical observations show it to be a dark smudge that resembles a gap in space. Therefore, a group of astronomers from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) in China went to radio frequencies to look inside the cloud. The team was led by Yan Duan and Di Li.
They examined the carbon monoxide signal, which may be used to identify structures within a gas cloud, using two separate radio telescopes. The Barnard 18 molecular cloud also had signs of a bubble structure.
“Through combined analysis with the Five College Radio Astronomy Observatory (FCRAO) survey of the Taurus molecular cloud, we found an outflow located at the centre of the molecular bubble,” said NAOC astronomer Yan Duan, first author of the team’s paper published in The Astrophysical Journal.
The Herbig-Haro object known as HH 319, which has already been recognised by astronomers, lives on Barnard 18. These are made when protostellar jets, which are propelled away from their source stars at extremely high speeds, collide with the molecular cloud and induce luminosity.
Li and his team’s discovery of HH 319 near the core of the outflow provides information on the bubble’s origin.
Calculations by the scientists indicate that activity from the two stars began sculpting the massive bubble in Barnard 18 around 70,000 years ago.
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