James Webb Telescope Detects a Huge Structure in the Middle of the Milky Way.
An unprecedented discovery
The James Webb Space Telescope has made a stunning
observation in the center of our galaxy, revealing at least 17 concentric rings
of cosmic dust. These formations come from the star system WR 140, located more
than 5,000 light-years from Earth. This system is composed of two massive stars
whose orbits cross approximately every eight years, causing interactions that
generate these circular patterns.
Formation of dust rings
Each time the stars approach each other in their orbits,
their powerful stellar winds —streams of gas ejected into space—collide,
compressing the gas and forming dust. This process generates visible rings or
"shells," which act as time records similar to the growth rings of a
tree. The image captured by the telescope reveals more than a century of dust
formation in the system.
Features of the WR 140 system
- Composed of two stars: a Wolf-Rayet (WR) star and an O-type star.
- The WR star is extremely massive, more than 25 times the mass of the Sun, and has lost much of its mass through powerful winds.
- Its companion, the O-type star, has about 30 times the mass of the Sun, while WR has about 10 times.
MIRI's role in observation
The MIRI (Mid-Infrared Instrument), developed jointly by
NASA and ESA, was crucial to this discovery. Thanks to its ability to detect
longer infrared wavelengths, MIRI can observe cold objects like these dust
rings that were previously invisible to ground-based telescopes. This
instrument also made it possible to identify the chemical composition of the
dust, which is primarily rich in carbon.
How is stardust formed?
Forming dust from gas is a complex process, comparable to
turning flour into bread. Wolf-Rayet stars expel heavy elements like carbon
into space. These elements, as they cool and encounter the winds of another
star, compress and transform into dust. The elliptical orbit of the WR 140
system causes this phenomenon to occur periodically rather than continuously,
as occurs in systems with circular orbits.
Cosmic impact and the possibility of new stars
These dust rings can have a significant impact on star
formation:
- Clearing the environment: Winds from the stars sweep the area of residual matter, allowing the rings to remain well defined.
- Formation of new stars: Dust can accumulate in the outer regions and become dense enough to form new stars and planets.
- Dust resilience: The preservation of dust layers demonstrates that dust can survive in the hostile environment of interstellar space.
A rare but crucial phenomenon
Although there are thousands of Wolf-Rayet stars in the
galaxy, only about 600 have been identified. They are rare because their
lifetimes are short, but they may have contributed significantly to the Milky
Way's cosmic dust history. Many of these stars are thought to have exploded and
formed black holes, leaving behind vast amounts of material for future stellar
generations.
The James Webb: A Window to the Past and the Future
The James Webb Space Telescope is designed to tackle the
universe's greatest mysteries. Thanks to its sensitivity and advanced
technology like MIRI, it's possible to detect previously invisible structures,
such as the dust rings in WR 140. This discovery provides the best evidence to
date that Wolf-Rayet stars may be key sources of material for star formation.
Conclusion
The discovery of these 17 concentric rings around the WR 140
system represents a crucial advance in our understanding of how stars influence
the cosmic environment. Through the James Webb Telescope, a new window opens
for the study of interstellar dust, stellar evolution, and the genesis of new
stars and planets.