All articles tagged with #metallicity
NASA's James Webb Space Telescope discovered unexpected dust production in the primitive galaxy Sextans A, revealing that stars can forge solid dust grains, including iron and silicon carbide, even with minimal heavy elements, reshaping our understanding of early galaxy evolution and dust formation pathways.
Astronomers have discovered a star, SDSS J0715-7334, with the lowest metallicity ever observed, potentially making it the most 'pristine' object in the universe, offering new insights into the earliest stars and conditions of the early cosmos.
New research suggests that stars engulfing ultra-short-period (USP) rocky planets may explain the pronounced differences in metallicity observed among sibling stars. These planets, which orbit very closely to their stars, can be consumed, leading to metal pollution in the stars. The study, by Christopher E. O'Connor and Dong Lai, indicates that between 3 to 30 percent of Sun-like stars may have engulfed such planets. The research highlights the potential for USP engulfment as a natural consequence of low-e migration scenarios in compact, multi-planet systems.
Astronomers using the Gemini-South telescope have discovered that the globular cluster Gran 5, located near the Galactic center, contains two distinct stellar populations with different metallicities. This finding, based on high-resolution near-infrared spectroscopy of seven stars, marks the first detection of such diversity in a low-mass globular cluster. The study suggests that Gran 5 is not linked to the Gaia–Enceladus–Sausage structure but is part of the Galactic bulge or disk, with its metallicity variation possibly due to different evolutionary processes or mass loss.
Scientists have successfully transformed pure water into a metallic state by bringing it into contact with an electron-sharing alkali metal, inducing conductivity and a golden sheen. This breakthrough, achieved without the need for extremely high pressures, provides insight into the phase transition of water and could facilitate the study of extreme high-pressure conditions within large planets. The research, published in Nature, offers potential for replicating conditions inside planets like Neptune and Uranus, where metallic hydrogen is thought to exist.
Scientists have discovered an ancient star, dubbed the "Barbenheimer Star," that defies current understanding of the cosmos. The star, which exploded in a supernova 13 billion years ago, left behind a cloud of unusual elements and birthed a puzzling star in its place. Its chemical composition, revealed through stellar archaeology, is unlike any other known star from the early universe, with an inverted metallicity and an overabundance of heavy elements. This discovery challenges existing models of element formation and supernova behavior, leaving scientists baffled and eager to uncover more cosmic oddities to piece together this cosmic puzzle.
Scientists have discovered an ancient star, dubbed the "Barbenheimer Star," with a unique mix of elements and a seemingly impossible death, baffling researchers. The star's unusual metallicity challenges current understanding of the early universe, as it had high concentrations of heavy elements and low levels of lighter ones. Its parent star, which should have collapsed into a black hole, also defies explanation. Further research is needed to uncover more cosmic oddballs and solve this stellar mystery.
Scientists have discovered that some of the largest and most intense regions of star formation are found in the smallest of galaxies, known as dwarf galaxies. This is because stars in dwarf galaxies are more likely to turn into black holes rather than explode in supernovas, resulting in a delay in blowing away their star-forming material. This delay allows star-forming regions in dwarf galaxies to grow in size and intensity, producing more stars. The presence of metals in stars also plays a role in their evolution, with high-metallicity stars more likely to produce powerful supernovas. These findings provide insights into star formation in early galaxies and the conditions during the "Cosmic Dawn" period after the Big Bang.
Astrophysicists using the James Webb Space Telescope (JWST) have discovered a surprising amount of metal, including carbon, in a galaxy only 350 million years after the Big Bang. This finding challenges our understanding of metal-free population III stars and sheds light on the formation of metals in the early universe. The detection may be attributed to the first generation of supernovae or the presence of a supermassive black hole in the galaxy. Further research and larger sample sizes are needed to provide a more definitive explanation.
The James Webb Space Telescope (JWST) has discovered a surprising amount of metal in a galaxy only 350 million years after the Big Bang. This challenges our understanding of the Universe's first metals and the existence of metal-free Population III stars. The detection of carbon in the ancient galaxy suggests it may be the result of the first generation of supernovae or associated with a supermassive black hole. The JWST's findings shed light on the early metallicity of the Universe and the formation of rocky planets and life. Further research and larger sample sizes are needed to provide a more definitive explanation for this discovery.
A study published in Proceedings of the National Academy of Sciences has found a correlation between the age of star systems and the frequency of hot Jupiters, large exoplanets that orbit close to their stars. The research team analyzed data for 383 Jupiter-sized exoplanets and found that hot Jupiters were more likely to be found around younger stars, with the frequency decreasing as star systems aged. The study also revealed that the frequency of hot Jupiters was related to the amount of metal in the host star, providing insights into the discrepancies between different exoplanet surveys.
The James Webb Space Telescope (JWST) has discovered that early galaxies in the universe defied the "cosmic rulebook" of star formation. By observing galaxies as far back as a few hundred million years after the Big Bang, the JWST found that these ancient galaxies produced fewer heavy elements than expected based on later galaxies. The team suggests that the lower metallicity may be due to the continuous influx of new, pristine gas from the intergalactic medium, diluting the heavy elements inside the galaxies. This discovery challenges current models of galactic evolution and sheds light on the fundamental processes that shaped the universe.
While we have yet to directly observe the first stars of the cosmos, a new study suggests that their direct descendants, known as second-generation stars, may be lurking in our own galaxy's halo. These stars can be identified by their ratios of carbon and magnesium to iron, rather than their iron-to-helium ratio. Stars with a high carbon-to-iron ratio likely formed from the remnants of a single first-generation star, while those with a lower ratio likely formed from a mix of first and second-generation material. As more sky surveys come online, it is expected that these second-generation stars will be discovered, providing insights into the early history of our universe.
The James Webb Space Telescope has observed the irregular galaxy NGC 6822, the Milky Way's nearest galactic neighbor that is not a satellite. NGC 6822 has low metallicity, making it an object of interest for understanding the early Universe. The study of this galaxy dates back to its discovery in 1884 and has contributed to our evolving understanding of the Universe. The observations with Webb aim to better understand star formation and the evolution of interstellar dust in low-metallicity environments.
Astronomer Keith Hawkins has used chemical cartography to identify previously undetected regions of the Milky Way's spiral arms. Chemical maps, which show the distribution of elements in the galaxy, allow astronomers to locate celestial objects based on their chemical composition. By mapping the metallicity (ratio of metals to hydrogen) in the Milky Way, Hawkins found that areas with higher metallicity aligned with the spiral arms, confirming their existence. This technique has the potential to transform our understanding of the galaxy's structure and formation. The Gaia space telescope, along with other powerful telescopes, is revolutionizing the study of the Milky Way by providing precise and comprehensive data on its chemical composition.