Amazing New Image Captures a Space Phenomenon, The James Webb Space Telescope has provided us with the clearest images ever of one of the many wonders of the cosmos.
Around 5,600 light-years away is a star that Webb’s infrared eye has revealed to have an unusual feature: concentric rings of light radiating outward from it.
The concentric rings are real, but the typical Webb diffraction spikes are not; they have a great and fascinating explanation.
Because of their interactions, the star is actually a binary pair of extremely rare stars in the constellation of Cygnus, and material is being ejected from it at regular intervals and spreading outward in shells into the surrounding area.
These dust shells emit infrared light, allowing a sensitive sensor like Webb’s MIRI to resolve them with great precision.
Wolf-Rayet star WR 140 and its hot, massive O-type star partner are both extremely unusual objects, making this star a colliding wind binary.
Wolf-Rayet stars are the most luminous, hottest, and oldest stars in the universe. They are at the conclusion of the main sequence. Hydrogen is severely depleted, whereas nitrogen or carbon content is high, and mass loss is rapid.
As a result of their extreme size and luminosity, O-type stars have extremely short lives.
Approximately 3,000 kilometers (1,864 miles per second) of rapid stellar winds are being expelled from both stars in the WR 140 system. As a result, they are both rapidly losing weight. Things on both stars appear to be proceeding normally.
The elliptical shape of their orbit is the most intriguing part of the situation. This means that rather than describing perfect circles, the stars form ovals, with a point where they are most distant from one another (apastron) and a position where they are nearest to one another (periastron).
The stars’ tremendous winds collide when they approach the periastron, a distance approximately a third greater than that between Earth and the Sun.
This causes shocks in the surrounding material of the stars, which in turn accelerates particles and produces intense radiation like X-rays. As the material in the colliding star winds cools, dust is also formed during these occurrences.
The animation below depicts this procedure from a top-down perspective and demonstrates what the system would look like.
Ultraviolet radiation from the two stars is absorbed by the dust, which is a type of carbon. This causes the dust to heat up, and its subsequent thermal radiation is what Webb detects at infrared wavelengths.
The stellar wind then pushes the dust further away, causing the partial dust shells to grow. As they are blown further away, they lose heat and density as they expand.
What you see in Webb’s photograph is reminiscent of a series of bubbles, with the edges of the dust shells standing out due to the increased concentration of material caused by the change in viewpoint.
The binary star’s orbit has a duration of 7.94 years, which means that wind impact and dust formation are regular occurrences. This means that the age of the apparent dust shell can be calculated by counting the rings of the nebula around the double, much like tree rings.
If the photograph was taken 160 years ago, the 20 visible rings would represent the dust shells that formed over that time. 2016 marked the most recent time a periastron of WR 140 was seen.
Researchers from the Institute of Space and Astronautical Science at the Japan Aerospace Exploration Agency, led by astronomer Ryan Lau, recommended that Webb observe WR 140.
They’re writing up their findings from the observations, so we might soon learn more about this peculiar star.