Tag Archives: Discs

Webb Uncovers Evasion Agent Discs That Create Exomoons Around Gas Giant Exoplanets

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Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have identified a carbon-rich disk encircling CT Cha B, a massive exoplanet located approximately 620 light years from Earth in the Chamaeleon constellation. This discovery offers the first direct insights into the chemical and physical characteristics of the gas giant and the materials that might contribute to its potential lunar system.

Artistic rendering of dust and gas discs surrounding a young exoplanet CT Cha b. Image credits: NASA/ESA/CSA/STSCI/G. CUGNO, University of Zurich & NCCR Planets/S. Grant, Carnegie Institution for Science/J. Olmsted, Stsci/L. Hustak, Stsci.

CT CHA, also referred to as PDS 44 and TIC 454259409, is merely 2 million years old and continues to accumulate materials for its formation.

However, the disks identified by Webb are independent of the larger accretion disks surrounding the central star.

“We can observe signs of disks around companion celestial bodies and explore their chemistry for the first time,” remarks Dr. Sierra Grant, an astronomer at the Carnegie Institution for Science.

“We are not merely observing the moon’s formation; we are witnessing the planet’s formation as well.”

“We are investigating the materials involved in forming planets and moons,” added Dr. Gabriele Kuno, an astronomer from the University of Zurich and the National Center for Capacity for Research Planets.

Infrared observations of CT CHA B have been captured by Webb’s MIRI (Mid-Infrared Instrument), which employs a medium-resolution spectrometer.

An initial examination of Webb’s archived data revealed evidence of molecules in the surrounding disk, prompting deeper analysis of the data.

The planet’s faint signal is obscured by the glare of its host star, requiring astronomers to utilize high-contrast techniques to separate the star’s light from that of the planet.

“We detected molecules in the planet’s vicinity, indicating there was something significant to delve into within the data, which took us a year of dedicated effort. It truly required a lot of patience,” Dr. Grant stated.

Ultimately, researchers identified seven carbon-containing molecules within the disk, including acetylene (C2H2) and benzene (C6H6).

This carbon-rich chemistry contrasts sharply with that found in the disks around the host star, where water was detected alongside carbon.

The disparity between the two disks suggests rapid chemical evolution occurring within just 2 million years.

“We aim to better understand how our solar system formed its moons. This necessitates examining other systems that are still in the process of development. We are striving to comprehend all the underlying mechanisms,” Dr. Cugno explained.

“What do these moons resemble? What are their components? What physical processes are in action, and what are the associated timescales?”

“Webb is capturing the narrative of moon formation, enabling us to explore these questions observationally for the very first time.”

The survey results were published today in the Astrophysical Journal Letters.

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Gabriele Cugno & Sierra L. Grant. 2025. A carbon-rich disk surrounding the planetary mass ally. ApJL 991, L46; doi: 10.3847/2041-8213/ae0290

Source: www.sci.news

Small Discs Can Ascend to the Upper Atmosphere Solely Using Solar Energy

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SEI 261839461

Illustration of a solar-powered levitating disc

Schafer et al. Nature

A tiny disc, roughly the size of a nail, has the potential to ascend to high altitudes in sunlight while carrying sensors through some of the coldest and thinnest parts of the atmosphere. These swarms, flying higher than commercial aircraft and balloons, could reveal new insights regarding Earth’s evolving weather and climate.

These floating devices harness a phenomenon known as photophoresis. This was initially discovered over 150 years ago when chemist William Crookes invented a radiometer, a device with black and white feathers that spin when they are exposed to sunlight. The wings absorb light and release heat, increasing the momentum of nearby gas molecules. Due to the difference in temperature between the black and white sides of the wings, the black side emits more momentum, allowing the air to flow in one direction with sufficient force to turn the wings.

“We’ve embraced this lesser-known physics to develop applications that could benefit many people, enhancing our understanding of how weather and climate change unfolds over time.” Ben Schafer from Harvard University.

To create the levitating disc, Schafer and his team designed a device that spans 1 cm, composed of two sheets of aluminum oxide filled with microscale holes. When illuminated, the lower sheet, which contains alternating layers of chromium and aluminum oxide, heats up more than the top layer, similar to the black sides of the radiometer blades. This generates a directional airflow that moves upwards instead of sideways.

Under white LED and laser illumination — set to an intensity that mimics about 50% of natural sunlight — this upward force successfully lifted the device. This represents progress over previous solar-powered flyers, which required light intensity significantly brighter than sunlight. However, the tests were conducted under laboratory conditions with air pressure much lower than Earth’s surface pressure.

Fortunately, such low pressure conditions are common at higher altitudes, especially in the Mesosphere, which spans 50-85 km above the Earth. Researchers indicate that increasing the disc’s size to 3 centimeters could enable it to carry a 10-milligram payload to hard-to-reach research areas at altitudes of 75 km. Schafer has co-founded a startup, Rare Feed Technology, aiming to commercialize fleets of these high-flying devices for environmental monitoring and communications.

After sunset, computer modeling indicates that these discs could utilize the heat radiating from Earth’s surface to remain airborne. “If they can stay afloat during the night, that represents a significant advancement instead of simply descending and landing.” Igor Bargatin from the University of Pennsylvania, who is conducting similar research.

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Source: www.newscientist.com