Dust is a nuisance in our houses. In space it is a basic material from which stars, planets and living beings are made. Understanding where cosmic dust comes from is a basic question in astronomy, and researchers who work with the JWST have uncovered a source: Wolf-Rayet stars.
Cosmic dust consists of tiny particles from nanometers to micrometers. These particles are the basic building blocks for chemical development, the formation of complex organic molecules and even play a critical role in star formation. There are different types of cosmic dust, including silica dust, carbon -based dust, metallic grains that contain iron or nickel and even ice -covered particles in the coldest regions in the room.
Cosmic dust is a backbone material, and astronomers have several questions that you actively ask. They want to know where dust comes from in the early universe when the first stars formed and only started to create heavy elements. How do dust grains grow in space? How do you survive the hard conditions of space? How do dust grains are liable in the early phases of planet formation?
Carbon Dust is of particular interest for all of this because life is based on earth on earth on earth and therefore plays a crucial role in interstellar chemistry and chemical development. The surfaces of carbon dust grains are chemically active and things like water, ammonia and methanol collect on their surfaces and enable chemical reactions that create complex organic compounds.
This illustration from separate research published in 2023 shows how complex organic molecules (Coms) are used on the surfaces of icy carbon dust grains at low temperatures. Photo credits: Tsuge et al. 2023. Natastr
The importance of simple dust cannot be overrated, and the astronomers have long wondered where it comes from, especially the most important carbon dust. New research in the Astrophysical Journal shows how Wolfsrayet (WR) stars generate dust and spread them into the Interstellar Medium (ISM). It bears the title “Carbon-rich dust, which is injected into the interstellar medium by galactic toilet bobs”, and the main author is Dr. Noel Richardson, Associate Professor of Physics and Astronomy at the Embry Riddle Aeronautical University.
Wolf-Rayet stars are an unusual class of star. They are extremely hot and their temperatures are between 30,000 and 200,000 Kelvin, which means that they are some of the hottest stars we know. They are also extremely bright and can surpass the sun millions of times. They have masses between 10 and 25 solar masses and may have been more massive when they formed for the first time. They also spend extremely powerful star winds that reach speeds of 5,000 km/second. This is millions of times faster than the wind of the sun.
These extreme objects are developed and WR stars represent stars in a short but important phase of their life. Her outer hydrogen has disappeared, used in the nuclear fire and they merge helium and heavier elements in their cores. Basically towards the end, ready to be destroyed in massive supernova explosions or to break in yourself and to shape the star mass of black holes.
“Wolfsrayet stars are essentially highly developed massive stars that do not show hydrogen at all,” said the main author Richardson in a press release. “They lost their hydrogen in the outside of the star and merged helium in their core, which means that they approach the end of their life cycle.”
All WR stars unleashed mighty, mighty star winds, and earlier examinations show that the winds for at least one wolf jet star collide with the winds of another star and condenses into carbon dust. This star is called WR-140. Astronomers believe that WR140 is the prototypical cosmic dust producer.
The JWST recorded this picture of WR-140 with its Miri instrument. The star has concentric dusts that have formed due to its binary relationship with another star. The rings were created in about 160 years. Photo credits: from NASA, ESA, CSA JWST Miri & Ryan Lau et al.; Processed by Meli Thev – own work, CC BY -SA 4.0
Dust around WR stars represents a paradox. The intensive external radiation pressure of the stars should simply turn them down, but the strong winds are necessary so that they form.
In their research, Richardson and his co-researchers examined four WR stars. They are a subtype of WR star called WCD stars, carbon-rich stars that are known for excess infrared emissions from surrounding dust. The stars in their sample are either in confirmed binary systems or are known to be subjected to the regular creation of dust.
“Not only did we find that the dust in these systems is durable and also escapes into space, but also found that this is not only for a system,” said Richardson.
One of the authors of the study is Dr. Ryan Lau from the NSF Noirlab. Lau was involved in the previous research with which the JWST WR-140 observed, the only previously known WR star that has a dust. Lau commented on the new observations and said: “It was confirmed that we see the same pattern of surviving dust shells that we made in other systems for WR-140,” said Lau. “These observations show that the dust produced by Wolf-Rayet stars can survive the hard, starry environment.”
The new studies confirm that in star pairs winds of a toilet star collides with the wind speeds of his companion and forms carbon dust. “Since this dust is carried near the WCD wind speed in the direction of the interstellar medium (ISM) and the binary file continues through its orbit, a spiral structure is formed by the system,” the authors write in their research. The shape of this dusty structure depends on orbits, mass loss rates and wind speeds.
The four Wolfsrayet stars in the rehearsal. “In all cases, we see large, extended structures around the stars that can be described as repeated dust structures that are similar to those who are observed with JWST by WR 140,” the authors write. Photo credits: Richardson et al. 2025. APJ
When WR-140 was observed, astronomers were able to surround 17 concentric dust shells around the binary date. In these new images, the four stars also showed concentric rings, a tellty sign that the creation of dust is episodic. “The regular distance from dust characteristics confirms the regular nature of dust formation, which corresponds to a connection to the binary movement,” the authors explain.
Not only that, but the observations show that the dust is durable in view of the intensive environment. “In this analysis, we show that the dust is durable, with the age of at least 130 years, but more than 300 years are found in some systems,” writes the researcher.
The team was also able to determine the movement of the dust and showed that it corresponds approximately to the wind speed. “We use these images to estimate the proper movement of the dust and find the dust so that you spread to ISM with the movement, which is comparable to the wind speed of the toilet stars,” they write.
The JWST observations also show some unexpected forms that resemble the PropllyDs by one of the four stars in their sample. “In addition to these results, we observe unusual structures by WR 48A that could represent dusty lumps that are shaped by photo -vaporation and windblation such as young ProPlyD objects,” explain the researchers. These structures show that the dust could be durable and “should be taken into account in galactic dust budgets”.
These pictures from research show the unusual dusty lumps that formed around the stars. These resemble the proposals and show that the dust is durable. Photo credits: Richardson et al. 2025. APJ 💾 update 🗑️ Delete
If WR stars can create dust that can endure over centuries, astronomers have to rethink how they think about dust and what role it plays in the event of a star development.
This work calms some of the gnails of astronomers who gnaw the curiosity on a cosmic dust, but there is much more work to do. “Where is this dust going?” Asked Lau. “We would like to find out exactly what the chemistry of this dust is. To do this, we have to take spectra in order to identify a specific grain composition – the physical properties – in order to receive an idea of the chemical contribution to the interstellar medium.”
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