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Category: energy

Did this star eat its planets? A new study offers clues on ‘chemical paradox’ of a binary system

Astronomers have investigated a puzzling binary star system in which two stars that may have formed together now show dramatically different chemical compositions. The new study, uploaded to the arXiv preprint server on May 29, hints at the possibility that one of the stars may have swallowed its own planets.

Generally, in binary systems, the two stars form from the same molecular cloud and, as a result, have the same age and chemical composition. Any differences in their metallicity, astronomers say, hint at an event involving mass transfer or engulfment of planetary components or other internal processes. HD 81,809 is one such peculiar system in which the stars are both sun-like G stars but are at different stages of evolution.

The primary star, HD 81809A, has crossed the main-sequence phase, depleted its hydrogen fuel in the core but hasn’t turned into a giant star yet—it is now a subgiant. On the other hand, the secondary star, HD 81809B, is still a main-sequence star. It has lithium enrichment and there is a difference in iron content between the two stars—the primary is metal-poor with an iron abundance of −0.57 dex, while the secondary has roughly solar metallicity around 0.00 dex.

New semiconductor building blocks make power converters smaller, more affordable

Researchers at the Department of Energy’s Oak Ridge National Laboratory incorporated gallium nitride semiconductors to create a high-efficiency power converter that is more compact, affordable, and efficient.

A power converter is a type of device that manages semiconductor switching and transforms current or voltage, so electricity flows smoothly and safely among equipment, power sources, and users.

Silicon semiconductors are the fundamental building blocks of conventional converters. Manufacturer ROHM Semiconductor provided the ORNL research team with gallium nitride semiconductors that enable switching 10 to 20 times faster than silicon while losing less energy in the process.

New propulsion system could make tiny satellites both fast and fuel-efficient

MIT engineers are testing a new propulsion system that combines the power and speed of conventional chemical thrusters with the precision and fuel-efficiency of electrical thrusters.

The system could enable the design of nimbler, more flexible small satellites, which could perform both fast, powerful maneuvers and slower, precise adjustments, depending on the mission and moment at hand.

The key to the new system is a special propellant that can power both chemical and electrical thrusters, which traditionally have required separate, bulky fuel sources.

Microcombs unlock 112Gbps wireless link at 560GHz for 6G

Researchers at Tokushima University have demonstrated single-channel wireless transmission at 112 Gbps in the 560 GHz band using soliton microcombs, marking a significant step toward next-generation 6G communications.

Conventional electronic technologies face fundamental limitations in generating stable high-frequency signals beyond 350 GHz, including reduced output power and increased phase noise. These challenges have hindered the realization of ultra-high-speed wireless communication in the terahertz regime, which is expected to play a key role in future 6G systems.

Microcomb system tackles key hurdles To overcome these challenges, the research team developed a microcomb-driven terahertz wireless communication system that combines fiber-coupled microcombs with high-order modulation techniques. The system leverages the high frequency stability and low phase noise of microcombs to generate a low-noise terahertz carrier.

Solar-powered desalination system turns ocean water into drinking water, without waste

The United Nations estimates that 2.2 billion people lack safely managed drinking water, and communities from California to the Middle East rely on desalination plants to convert ocean water to fresh water. Common desalination techniques such as reverse osmosis and thermal distillation are energy-intensive, require pre- and post-water treatment, and leave behind a concentrated saltwater byproduct called brine that wreaks havoc on sea life when it’s deposited back into the ocean by raising the salt level and lowering oxygen in the water.

Diamond quantum sensor could reveal elusive altermagnets

For nearly a century, there were two known kinds of magnets. Ferromagnets are the classic magnets that attract metal and keep pictures stuck to the refrigerator. Antiferromagnets hide their magnetism at the atomic scale but are increasingly prized for their technological potential. A third category discovered within the last decade may combine the best qualities of both. Dubbed altermagnets, they could someday help create faster, more energy-efficient electronics.

Now, University at Buffalo physicists are proposing a quantum sensing system to make identifying altermagnets much simpler. Described in a study published in Physical Review Letters, the theoretical technique would measure how a suspected altermagnet disturbs a tiny magnetic defect in a nearby diamond. The way the defect’s magnetic signal relaxes could provide evidence of altermagnetism.

“This could be the first building block of a new generation of experiments that determine whether a material is an altermagnet,” says corresponding author Jamir Marino, Ph.D., assistant professor in the UB Department of Physics, College of Arts and Sciences. “Altermagnets could completely revolutionize the way we transport information, but to confirm if this elegant theory is true, we need experiments that identify altermagnets and confirm they behave the way scientists predict.”

Ultrafast holographic imaging reveals electron and magnetic dynamics inside next-generation materials

An extremely fast microscopy method to research the interaction of light and matter makes it possible to study optical processes on very short timescales. To this end, a German–Italian research team is combining holographic imaging with ultrafast spectroscopy in an innovative way. In this manner, even extremely short-lived electronic and magnetic phenomena—which play a major role in the development and application of novel energy materials—can be observed.

The research was conducted as part of an international collaboration between scientists from the Institute for Physical Chemistry at Heidelberg University, the Polytechnic University of Milan, and the Institute for Photonics and Nanotechnologies in Milan (Italy). The findings are published in the journal Nature Photonics.

At the heart of the research is a pump-probe microscope, which is used to conduct so-called excitation and detection experiments. In this process, the material under investigation is first excited by a short light pulse, while a second pulse records the time-dependent response. By comparing measurements taken with the excitation on and off, these processes can be accurately reconstructed.

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