Physics and Astronomy Blog

This artist’s impression of a planet-forming disk surrounding a young star shows a swirling “pancake” of hot gas and dust from which planets form. Using the James Webb Space Telescope, a team of researchers obtained detailed images showing the layered, conical structure of disk winds – streams of gas blowing out into space. National Astronomical Observatory of Japan (NAOJ)

Using data from NASA’s James Webb Space Telescope (JWST), researchers such as Clemson University’s Sean Brittain captured the most detailed images yet of protoplanetary disk winds—streams of gas that shape the disks where planets form. These winds may solve the mystery of how disks lose angular momentum, enabling gas to accrete onto young stars much faster than previously thought. The study, published in Nature Astronomy, observed four protoplanetary disk systems: a complex, three-dimensional structure of winds originating from different regions of the disk, which resembles a layered onion.

The findings provide the first tangible evidence supporting the theory that magnetic field-driven winds play a key role in star growth and disk evolution. Thermal winds and X-winds also contribute. By tuning JWST’s detectors to specific molecules, the team traced the layers of these winds and discovered a central hole in the cone-shaped structures, formed by molecular winds. These insights could refine our understanding of planet formation and stellar evolution. The researchers now plan to expand their observations to more disks to deepen their knowledge.

Credit: David Brandin

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James Webb Space Telescope reveals evidence of winds that could solve mystery of how planet-forming disks are shaped | Clemson News

Clemson University researchers, led by Laura Finzi, have uncovered the role of mechanical forces in gene transcription, specifically in RNA polymerase (RNAP) activity during termination. While the traditional view holds that RNAP dissociates from DNA after releasing mRNA, the team demonstrated that force can cause RNAP to slide forward or backward on the DNA template. This force-directed recycling allows genes to be transcribed multiple times or only once, affecting gene expression.

Using magnetic tweezers, the researchers found that RNAP’s ability to switch to oppositely oriented promoters relies on the C-terminal domains of its alpha subunits. Deleting these subunits prevents RNAP from flipping to oppositely oriented promoters. Published in Nature Communications, these findings could inform strategies for regulating transcription and suppressing harmful proteins. Finzi envisions a future where a map of forces on the genome helps predict transcription levels across genes and cells. The study was supported by NIH grants.

Credit: David Brandin

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Research provides new insights into role of mechanical forces in gene expression | Clemson News

Above: a YouTube video related to Dr. Lehmacher’s NASA VortEx rocket launched on 23 March 2023 from Andøya Space Center, Norway.

The video shows a very detailed simulation of the winds and waves over northern Scandinavia based on the actual weather conditions and including the time when we launched two sounding rockets. 

The high-resolution (1.2 km) weather simulation was made at the German Climate Computing Center (DKRZ) by a collaborator, Prof. Claudia Stephan, of Dr. Lehmacher at Clemson University from the Institute for Atmospheric Physics (IAP) at the University of Rostock and covers waves at heights up to 40 km. The waves are excited by winds blowing over the coastal mountains and propagate upward into the stratosphere. The goal of VortEx is the study of mixing effects from these waves at even greater heights, in the mesosphere and lower thermosphere, 50 to 120 km. This intermittent mixing can extend even further, to the region where the space station orbits (400 km) and the surrounding ionosphere and become part of our “space weather”.

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Rocket launch could provide insight into how turbulence far above the planet’s surface affects our planet’s atmosphere | Clemson News

A little over three decades ago, the only planets we could confirm were the ones in our solar system. But with the advent of more powerful telescopes on the ground and new observatories in space, scientists have since discovered the existence of thousands of exoplanets orbiting stars other than our sun. According to Janus Kozdon, a graduate student in the Clemson University Department of Physics and Astronomy, the vast majority of the observed exoplanets orbit older stars, with very few found orbiting young stars, who are still forming protoplanetary disks from gas and dust. Kodzon says detecting planets in these young systems is challenging because the disk can obscure the planet’s signature. Kodzon and his team developed a novel technique to study planets surrounding young stars through disk morphology, which he plans to the June American Astronomical Society meeting in Madison, Wisconsin.

Kodzon’s research, published in the Astronomical Journal in August 2023, focuses on CI Tau, a young star located about 523 light-years away, where an exoplanet was already discovered within its protoplanetary disk. Observing CI Tau for nine nights, Kozdon used spectroscopy and his custom model to analyze carbon monoxide in the disk, revealing its two oppositely oriented components. The findings from this research provided the first empirical evidence of disk eccentricities potentially caused by the embedded planet. Sean Brittain, Clemson’s associate provost and dean of undergraduate learning; Jeffrey Fung, assistant professor in the Department of Physics and Astronomy; and physics graduate students Stanley Jensen and John Kern also worked on the project. This work sheds light on planet-disk interactions and opens new avenues for studying forming planets around young stars.

Researchers/collaborators from the University of Maryland, the National Science Foundation National Optical-Infrared Astronomy Research Laboratory, and Texas State University were also involved in the research.

Credit: David Brandin

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Clemson grad student’s study sheds light on planet formation in infant stars | Clemson News

In our universe, only about 15% of matter is known or seen, while the remaining 85% is known as dark matter, a substance that remains largely unexplained by scientists. Circiello, a graduate research assistant in the Department of Physics and Astronomy at Clemson University, recently presented his research at the American Physical Society’s April meeting, one of the largest conferences in the field. He explained that dark matter is confirmed to exist through its gravitation effects, despite its elusive nature. Circiello emphasized that since dark matter significantly influences cosmic structures and dynamics, understanding this type of matter is key to solving some of the universe’s largest secrets. The research Circiello presented built on that done by colleague Alex McDaniel, which explored new ways by which to detect dark matter, often through looking at nearby, dark-matter-dominated galaxies.

Credit: David Brandin

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Gamma-rays and galactic mysteries: Clemson astrophysicist studies dark matter’s secrets | Clemson News

Clemson Department of Physics and Astronomy Professor, Feng Ding, and his international collaborators “have discovered a cause of blood vessel damage in the brain that plays a role in Alzheimer’s disease-related dementia.”

Clemson University researcher Feng Ding and his collaborators have identified a mechanism behind blood vessel damage in the brain that contributes to Alzheimer’s-related dementia. Their findings, published in Nature Communications, shed light on how amyloid beta oligomers—byproducts of amyloid precursor protein—damage the blood-brain barrier. This disruption allows amyloid plaques to form on blood vessel surfaces, a condition present in 95% of Alzheimer’s patients.

The study reveals that amyloid beta oligomers break into nanoparticles that compromise endothelial cell junctions, creating holes in the blood-brain barrier. This damage not only affects neuronal function but also causes extensive vascular harm, offering a potential target for new Alzheimer’s therapies. The research, supported by NIH, provides critical insights into the interplay between amyloid aggregation, vascular health, and neurodegeneration.

Credit: David Brandin

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Research reveals cause of vascular changes associated with early Alzheimer’s  | Clemson News

Three members of Rao’s lab- Mihir Parekh, postdoctoral fellow, and graduate students Janak Basel and Nawraj Sapkota have discovered a way to optimize electrolytes to address the short circuiting and rapid capacity loss problems in sodium-ion batteries. These batteries are less expensive and more readily available than lithium-ion batteries. 

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Electrolyte research by Clemson physicists could lead to cheaper high-capacity batteries. | Clemson News