In August, an early release image from the James Webb Space Telescope showed a strange sight: as many as 17 rings around a star system. Was it an alien structure or an optical illusion?
Dust is the answer. A paper published in Nature Astronomy explains how stellar winds blow dust into circles when the two stars are close together.
The mechanical driving force is the stellar winds. The arcs of dust created by the stellar winds when they are close to each other can be seen on the sky.
An O-type star 30 times the mass of the Sun and a Wolf-Rayet companion 10 times the mass of the Sun can be found in the exotic, odd-couple stars inWR-140. The Wolf-Rayet 140 system is the only one that makes nested dust shells.
About twenty years ago, these hemispheres or partial shells of dust were first seen in the ground.
Morris said that the ground-based observations only detected a couple of inner shells. They thought they were dust from the massive O star and the more evolved Wolf-Rayet star.
The science team was astounded by the new observations with the Mid-Infrared Instrument.
While the features were not unexpected, the number, spatial extent, and clarity of them certainly stunned all of us to the point that the team made intensive work of confirmation their astrophysical reality of tracing over 130 years of dust production episodes, about once every 8 years.
Ryan Lau, an astronomer at the National Science Foundation's NOIRLab, is the leader of the new JWST observations. When the stars come close together every 7.93 years, they create enough pressure on the stars to form dust.
Dust production conditions in the colliding stellar winds are ideal during those periodic close approaches.
Dust plays a major role in the evolution of the universe and is an essential ingredient for new stars and planets. One of the basic uses of the new telescope is to learn more about the properties of dust in the universe, as it can provide snapshots of the contents, conditions and processes operating in galaxies.
Morris thinks that the early observation of WR-140 was due to that.
The proposal was to investigate a class of massive stars that may be some of the first producers of dust in the early Universe. The emission from the centralbinary is very high in the range of sensitivities and the shell emission is very weak.
Even with the unique nature of WR-140, the researchers never imaged they would be able to see the physics of these two stars.
Morris said that the clarity of the 17 or 18 partial shells caught him off guard, and that the winds of the O star have "cleared out" the surrounding medium over 1000s of years.
Astronomers can use these observations to understand the evolution of our solar system. The solar system was formed in the swept-up gas and dust of a bubble formed by a star, and meteorites found on Earth contain evidence of elements processed in the core of the star.
It is possible that the pre-solar nebula collapsed in the wind-blown material and was enriched by the core evolution of the star. Morris made a statement. With NASA's new space telescope, we will learn a lot more about how these stars shape the material between stars.
There is more reading to be done.
The nature of astronomy.
The JPL Press is releasing.
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