The universe is truly full of wonders, and the James Webb Space Telescope has given us the best images of one of them yet.
The object in question is a star about 5,600 light-years away, and Webb’s infrared eye detected an extraordinary detail: It’s surrounded by what appear to be outwardly radiating concentric rings of light.
While Webb’s property diffraction spikes These concentric rings are not ‘real’ – and there is a wonderful and fascinating explanation for them.
The star is actually a binary rare star pair in the constellation Cygnus, and their interactions produce definite periodic dust bursts that expand outward in the crusts over time.
These dust shells glow in the infrared, which allowed for an instrument as sensitive as Webb’s. MIRI To solve them in exquisite detail.
The star is what is known as an extremely rare colliding wind binary. Wolf-Rayet A star called WR 140 and a hot, large O-type star companion – another rare object.
Wolf-Rayet stars are very hot, very bright, and very old; at the end of their main series life. They are significantly depleted in hydrogen, rich in nitrogen or carbon, and lose mass at a very high rate.
O-type stars are among the most massive stars known, and are also very hot and bright; because they are so big, their lifespan is incredibly short.
Both stars in the WR 140 system are fast stellar windsIt is blowing into space at a speed of about 3,000 kilometers (1,864 miles) per second. Therefore, both are losing mass at a fairly drastic rate. So far so normal for both stars.
The interesting place is their orbit, which is elliptical. This means that the stars do not define beautiful, regular circles around each other, but ovals, the point where they are farthest from each other (apastron) and the point where they are closest to each other (periastron).
When the two stars enter the periastron—about one-third the distance between Earth and the Sun—they get close enough for their strong winds to collide.
This creates shocks in the material around the stars, accelerating particles and producing energetic radiation such as X-rays. These colliding winds also trigger dust formation events as the material in the colliding stellar wind cools.
This process can be seen in the animation below, which shows how the system will look from top to bottom.
Dust is a form of carbon that absorbs ultraviolet light from two stars. This heats the powder and causes it to re-emit the thermal radiation observed by Webb at infrared wavelengths.
The dust is then blown outward by the stellar wind, resulting in the expansion of partial dust shells. As they are blown out, they expand and cool, losing heat and density.
What you’re looking at in Webb’s image is a bit like a string of bubbles; The edge of each dust shell is more visible because you’re looking at a denser concentration of material because of perspective.
Since the binary star’s orbit has a period of 7.94 years, wind collision and dust generation occur like clockwork every 7.94 years. This means you can count the rings of nebulae around the binary system, such as tree rings, to determine the age of the outermost visible dust shell.
About 20 rings are visible, meaning you can see dust shells that are about 160 years old in the Webb image. The WR 140 periastron was last observed in 2016.
Webb’s WR 140 observation was requested by a team led by astrophysicist Ryan Lau of the Japan Aerospace Exploration Agency’s Institute of Space and Space Sciences.
them preparing an article on observationsso it’s possible that we’re on the verge of finding something new about this fascinating, crazy star.
