Low metallicity stars. 5 Z⊙, is one of the lowest-metallicity star Mar 1, 2016 ·...
Low metallicity stars. 5 Z⊙, is one of the lowest-metallicity star Mar 1, 2016 · Around mid-to-late M-dwarf stars with low metallicity, planetary rotation rates at the inner edge of the HZ become faster, and the inner edge of the HZ is farther away from the host stars than in previous GCM studies. The X-ray output of low-metallicity starburst galaxies is a key component of stellar feedback, tracing the processes responsible for gas ionization and chemical enrichment. Oct 10, 2008 · Star F ormation at V ery Low Metallicit y. 1017 4 days ago · A new study looking at the isotopic ratios in interstellar comet 3I/ATLAS after its closest approach to our star has suggested it may have formed around an old, low-metallicity star in the Milky Way's outer disk. Jun 3, 2025 · This discovery marks the lowest metallicity contact binary candidate observed to date. S284p1, about 11 solar masses, has grown from a dense gas clump over 300,000 years. A new study looking at the isotopic ratios in interstellar comet 3I/ATLAS after its closest approach to our star has suggested it may have formed around an old, low-metallicity star in the Milky Way's outer disk. Proceedings of the International Astronomical Union, 6. Low metallicity objects, such as Population II stars, are typically found in older stellar populations and have lower metal content. 4 days ago · By connecting this object to similar low-metallicity stars in our galaxy, astronomers are beginning to trace a consistent picture of early element formation across different environments. S. The rest of this article is behind a paywall. 6 days ago · By searching for these rare, low-metallicity stars and deriving their chemistry, scientists can better understand the mechanisms of initial element production in the universe. 7 parsecs) from the Solar System, it is a relatively nearby star and the closest solitary G-class star The Binarity at LOw Metallicity (BLOeM) survey is an ESO large programme designed to obtain multi-epoch spectroscopy for 929 massive stars in the Small Magellanic Cloud (SMC). Feb 27, 2026 · This galaxy has a known gas-phase metallicity and is too young for low-mass asymptotic giant branch stars to have contributed significantly, providing a clean environment to isolate massive-star yields. A new study looking at the isotopic ratios in interstellar comet 3I/ATLAS after its closest approach to our star has suggested it may have formed around an old, low-metallicity star in the Milky 1 day ago · This suggests it coalesced around a star with very low “metallicity” – meaning it contained fewer elements heavier than hydrogen and helium. The Milky Way galaxy has four main stellar populations: 1) the halo stars with low metallicities 1 and eccentric orbits, 2) the bulge population with a large range of metallicities and dominated by random motions, 3) the thin disk stars with an average metallicity < [Fe / H]> = -0. “That’s where we’ll find the first planets that formed. Bernini-Peron, M. The energy generated is the product of nuclear fusion of hydrogen into helium by way of the proton–proton (PP) chain. Nov 7, 2024 · Therefore, the dominant mode of star formation (and possibly planet formation) as well as the relevant physical/chemical processing of the ISM in the cosmic history should have occurred in low-metallicity environments. Aug 26, 2015 · The abundances of the low-metallicity stars they found are consistent with globular cluster metallicities, suggesting that these stars (about 6% of the sample) may have arrived in the nuclear star cluster as a result of the infall of globular clusters. This upper limit decreases with increasing metallicity gradually without remarkable sudden drops. , Sander, A. The simulations show a prominent Apr 18, 2023 · Our findings imply that planets hosted by stars with low metallicity are the best targets to search for complex life on land. Finally, we evaluate the upper limit on the stellar mass set by stellar feedback. Understanding the metallicity of stars and galaxies is essential for studying their formation, structure, and dynamics. I discuss the physics of their formation, and how they transformed the early universe from an initially very simple state into one of ever increasing complexity. g. Its name is a Bayer designation that is Latinized from τ Ceti, and abbreviated Tau Cet or τ Cet. Due to the inverse correlation between LX/SFR Article: Supernova dust formation and the grain growth in the early universe: the critical metallicity for low-mass star formation Jun 10, 2007 · Among stellar observations we start with available observations of individual events before analyzing low-metallicity stars, which witness r-process contributions in the early Galaxy. 3–0. The common picture is that these low-metallicity stars are… Expand The stream’s low metallicity, combined with the spur feature, suggests a possible dual origin: a globular cluster or a dwarf galaxy. On July 1 last year, the Asteroid Terrestrial-impact Last Alert System detected an object racing through JWST reveals TOI-5293Ab’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. Mar 16, 2022 · ABSTRACT Low-metallicity stars give rise to unique spectacular transients and are of immense interest for understanding stellar evolution. Nov 3, 2010 · We study the evolution of low‐metallicity star‐forming clouds and discuss their fragmentation mass scales. May 28, 2024 · Conversely, low-metallicity stars, often found in older galactic regions, are typically smaller and have longer lifespans due to their slower consumption of nuclear fuel. We compare the relative occurrence of these two architectures as a fraction of detected planetary systems to determine the role that metallicity plays in planet formation. The findings show that massive stars can form in a structured way, even in Since cosmic metallicity increases in time with the evolution of universe, the formation of stars at low metallicities, especially the determination of their characteristic mass scales, is important for understanding properties of high redshift galaxies and the early history of the Milky Way. Sep 29, 2020 · The kinematics of the most metal-poor stars provide a window into the early formation and accretion history of the Milky Way. , Brands, S. Mar 1, 2026 · The orbits of the least chemically enriched stars open a window on the formation of our Galaxy when it was still in its infancy. 0 dex. 5$). Recent studies have shown that a non-negligible fraction of them have prograde planar orbits, which makes their origin a puzzle. , Najarro, F. , et al. Low-metallicity star formation poses a central problem of cosmology, as it determines the characteristic mass scale and distribution for the first and second generations of stars forming in our Universe. Hence, the first stars in the universe (very low metal content) were deemed population III, old stars (low metallicity) as population II, and recent stars (high metallicity) as population I. Jan 9, 2022 · A discovery in the Milky Way reveals a stellar structure called C-19, characterized by extremely low metallicity, offering new perspectives on early universe star formation and challenging traditional stellar formation theories. Moreover, the formation of low-metallicity stars is intricately linked to galaxy I describe (i) our recent updates on first star formation, with particular emphasis on their binaries, (ii) formation of low-metallicity stars and the transition of their initial mass functions with metal enrichment, and finally (iii) formation of supermassive stars from slightly metal-enriched gas by the newly found super-competitive accretion channel. The cooling induced by dust grains promotes fragmentation at small scales and the formation of low-mass stars In systems with detected planets, hot-Jupiters and compact systems of multiple planets are nearly mutually exclusive. The lowest-metallicity stars known are, in this sense, direct records of individual supernovae from the universe’s very first epoch. M. The greater importance of initial conditions compared to metallicity Results. Context. Mass-Loss Rate of Red Supergiant Stars in the Small Magellanic Cloud'. Planetary accretion cannot compete with gas dissipation around low-metallicity stars because the number density of planetesimals is low16–18 and gas disks dissipatesooner around low-metallicity Predictions from nucleosynthetic models for low-mass, low-metallicity asymptotic giant branch (AGB) stars account for the derived F abundances, while the upper limits on F content derived for most of the stars are lower than the predicted values. We present projected rotational velocities (v sin i) of all sources, and, using The prograde-to-retrograde asymmetry is also already in place in these metallicity ranges for in situ stars, either by number, with 3394 prograde stars and 2033 retrograde stars for the MP+VMP 12 hours ago · Unlike typical stellar streams, C-19 is a rare and significant find due to its extraordinarily low metallicity, below -3. The trouble has been that nobody knew where these ancient halo stars actually came from. Jan 5, 2022 · Only the tiny but very precise movement of the star measured by the Gaia spacecraft and the observation of its metallicity in the metallicity map from the Pristine survey made it possible to isolate this star as part of the remnant of an exceptionally low metallicity stream of stars. 9 M⊙) on the main-sequence or the gi-ant phase. Red dwarfs are very-low-mass stars. Chemistry as archaeology. It has been suggested that a later-formed rotating bar could have driven these old stars from Abstract. We do not detect significant HF absorption (∼2 σ) and derive a conservative 5 σ upper limit of . Thus, here, in the first of a series of papers, we introduce the Low-metallicity Star Formation (LZ-STAR) survey of the Sh2-284 (hereafter S284) region, which, at Z ∼ 0. Jun 10, 2004 · Our findings indicate that metallicity plays a major role in regulating the formation of low-mass stars. Sep 2, 2025 · For the low-metallicity environments of high-redshift galaxies, constraints on the multiplicity properties of massive stars over the separation range leading to binary interaction are crucially 3 days ago · In stars, metallicity affects their luminosity, temperature, and lifespan. 98. Follow-up high-resolution spectroscopy will reveal detailed chemical abundance patterns. These stars extend out to ∼7 kpc from the solar neighborhood and cover the main Galactic stellar populations, including the thick disk and the inner halo. Jan 5, 2026 · This poses a challenge to constrain the atmospheric properties of KELT-7b and two possible scenarios emerge from equilibrium chemistry and free chemistry retrievals: a high-altitude cloud deck muting all features or an extremely low metallicity atmosphere, respectively. In low-metallicity gas, the higher accretion rate and lower opacity result in weaker feedback and then higher up-per mass limit. [15] As a result, they have relatively low pressures, a low fusion rate, and hence, a low temperature. [Fe/H] $\\leq-2. C. Oct 21, 2024 · This discovery marks the lowest metallicity contact binary candidate observed to date. 265-270 doi:10. Objects with high and low metallicities are found at all redshifts. If you don't know of our interstellar visitor by now, here is a brief recap. Starting from a turbulent cloud core, we follow the formation and growth of protostellar systems with different metallicities ranging from 10 −6 to 0. Jan 13, 2022 · Given their low metallicity, high gas content and ongoing star formation, these objects are supposed to resemble the first galaxies that formed at the earliest epochs, and may thus represent a Sep 7, 2021 · Massive stars in the Small Magellanic Cloud (SMC, \ (\sim \) 1/5Z ⊙ ) currently serve as templates for low-metallicity objects in the early Universe, even though significant differences with respect to massive stars with poorer metal content have been reported. This makes it the most metal-poor stellar population ever discovered, offering unique insights into the early stages of galaxy formation and the behavior of dark matter. Jun 7, 2023 · The chemical composition of the Galactic halo star J1010+2358 shows extremely low sodium and cobalt abundances, different from most other halo stars, indicative of a very metal-poor star being Dec 5, 2022 · On the right, we show the stellar mass in bins of metallicity, without normalizing; the colour of the curves denote the galaxy stellar mass. From the structure of the envelope at the time of protostar formation, we derive the protostellar accretion rate and calculate the evolution of protostars in the main accretion phase. The most plausible explanation of their observed s-enhancement is mass transfer by stellar winds in binary systems from a primary companion while on its asymptotic giant branch (AGB) phase (now a white dwarf). \\textbf{By making use of advanced stellar evolution models generated by the Geneva Stellar Evolution Code (GENEC JWST reveals TOI-5293 A b’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. JWST reveals TOI-5293 A b’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. Tau Ceti is a single star in the constellation Cetus. 5% of the Sun is made up of two light chemical elements, hydrogen The evolution of stars is governed by three main parameters, which are the initial mass, metallicity (Z) and rotation rate. 1 Z ⊙. May 8, 2025 · The models include different phases of a star’s life—hydrogen burning and helium burning—and account for both non-rotating and rotating stars. Low metallicity stars are typically hotter and more massive than high metallicity stars, leading to differences in their evolution and eventual fate. 0, including 306 CEMP candidates, and confirming transverse velocities as a selection criterion for low-metallicity candidates. Aug 1, 2022 · The halo’s metallicity distribution function is also more mixed 126 and it contains an unexpectedly large number of high [α /Fe] abundance stars at high metallicity compared with the dSphs 102 Nov 14, 2023 · The most metal-poor stars (e. Speci ̄cally, I address the role of heavy elements in bringing about the transition from an early star formation mode dominated by These are old stars of low initial mass (M < 0. 4). Internal mixing, induced Mar 26, 2025 · The LZ-STAR survey explores low-metallicity star formation in Sh2-284, focusing on the massive protostar S284p1. We determine the nature of the two stars in the binary by using the eclipsing binary modeling software PHysics Of Eclipsing BinariEs (PHOEBE) to train a neural network to fit our observed panchromatic multiepoch photometry. Nov 24, 2021 · Low-metallicity stars rely on TDU to bring fresh, primary carbon into the envelope to produce primary nitrogen. 1 day ago · The stream’s low metallicity, combined with the spur feature, suggests a possible dual origin: a globular cluster or a dwarf galaxy. Aug 16, 2023 · AI-powered analysis of 'Evolved Massive Stars at Low-metallicity V. It will provide binary fractions and orbital configurations of binary systems and search for dormant black hole binary candidates (OB+BH). 5$) are the ancient fossils from the early assembly epoch of our Galaxy, very likely before the formation of the thick disc. Their importance has only grown further with the recent detections of mergers of stellar mass black holes that likely originate mainly from low-metallicity progenitor systems. , Oskinova, L. This is the reason why we need to care about the physics and chemistry of the low-metallicity star-/planet-forming regions. If we take the NSD data at face value, without considering possible contamination from bulge stars, we find that a formation scenario based on the inner disc's flowing gas is inconsistent with the low-metallicity tail of the observed metallicity-distribution function. Bomans, Dominik J. Most of the planned ground-based and space-borne telescopes are aimed at observing the first galaxies in which the gas metallicity is supposed to be very low. 5 dex and circular orbits, and finally 4) the thick disk stars which possess chemical and kinematical properties Sep 7, 2021 · ABSTRACT We study star cluster formation in a low-metallicity environment using three-dimensional hydrodynamic simulations. Aug 26, 2025 · Although these low-metallicity stars are beyond the range of our current sample, enrichment signatures may still be detectable in the evolution of the 16 O/ 18 O as a function of metallicity (Fig. Because low metallicity stars are dicult to observe directly, cosmo-logical simulations are crucial for understanding their formation. The ̄rst generations of low-metallicity stars formed at the end of the cosmic dark ages. We assemble the most complete and clean red supergiant (RSG) sample (2,121 targets) so far in the Small Magellanic Cloud (SMC) with 53 different ban Explore with advanced AI tools for machine learning research. , Verhamme, O. High-metallicity stars experience much less efficient TDU and thus to an extent rely on their inherent higher levels of carbon to make secondary nitrogen in the envelope. The common picture is that these low-metallicity stars are… Expand Jan 9, 2022 · A discovery in the Milky Way reveals a stellar structure called C-19, characterized by extremely low metallicity, offering new perspectives on early universe star formation and challenging traditional stellar formation theories. These stars influence their surroundings through intense UV radiation, strong winds and explosive deaths. Stars and nebulae with relatively high abundances of heavier elements are called metal-rich in discussions of metallicity, even though many of those elements are called nonmetals in chemistry. Here, we use 5~high-resolution cosmological zoom-in simulations ($\\sim~5\\times10^6$ star particles) of Milky Way-like galaxies taken from the NIHAO-UHD project, to investigate the origin of low-metallicity stars ([Fe/H]$\\leq-2. 5 < [Fe/H] < −0. We conclude The Binarity at LOw Metallicity (BLOeM) survey is an ESO large programme designed to obtain multi-epoch spectroscopy for 929 massive stars in the Small Magellanic Cloud (SMC). In a new study, astronomers report novel evidence regarding the limits of planet formation, finding that after a certain point, planets larger than Earth have difficulty forming near low-metallicity stars. 5 days ago · Meet PicII-503, One Of The Most Chemically Primitive Stars That’s Ever Been Discovered This might be among the very first of the second generation of stars. Moreover, the formation of low-metallicity stars is intricately linked to galaxy Nov 23, 2025 · In astronomy, metallicity is commonly classified into three main categories: low metallicity, intermediate metallicity, and high metallicity. It is important to study how star formation occurs in different galactic environments. 4% metallicity. Spectrally, this star is similar to the Sun, although it has only about 78% of the Sun's mass. , Crowther, P. Feb 9, 2026 · At very low metallicities, s-process production in massive stars is expected to be negligible in non-rotating models owing to three key factors: the scarcity of the $\\rm ^{22}Ne$ neutron source, the presence of primary neutron poisons, and the declining abundance of iron seeds. Jul 22, 2015 · Astronomers know this because a significant number of stars within globular clusters have very low metallicity, or metal content, which means they were formed before generations of stars had Oct 4, 2010 · Low-metallicity star formation is particularly important in the context of the formation of primeval galaxies. The integrated X-ray luminosity (LX) from high-mass X-ray binaries in star-forming galaxies scales with the star formation rate (SFR) and the host galaxy metallicity Z. The presence of heavier elements is the result of stellar nucleosynthesis. Using the sun as a baseline, astronomers can measure when a star formed by determining its metallicity, or the level of heavy elements presen In low-metallicity gas, the higher accretion rate and lower opacity result in weaker feedback and then higher up-per mass limit. Since metallicity affects how easily a star can lose mass through winds, the study tests how these winds behave in such extreme, low-metal environments. Hence, these stars emit relatively little light, sometimes as little as ⁄10,000 that of the Sun, although this would still imply a This uniformity was probably not predictable a priori, since n-capture abundances in r-processYrich low-metallicity stars reflect con-tributions from a single supernova or a small number of super-nova events, while the solar system (hereafter, SS) abundances result from many generations of supernovae. V. Believe of it like a first-generation star system, born shortly after the Big Bang when the universe was still relatively pristine. Moreover, the formation of low metallicity stars is intricately linked to galaxy evolution, in particular to early enrichment and to later accretion and mixing of lower metallicity gas. The evolution is also influenced by the presence of magnetic fields and of a close binary companion. Jun 30, 2014 · Abstract Low-metallicity star formation poses a central problem of cosmology, as it determines the characteristic mass scale and distribution for the first and second generations of stars forming in our Universe. We determine the nature of the two stars in the binary by using the eclipsing binary modeling software (PHysics Of Eclipsing BinariEs; PHOEBE) to train a neural network to fit our observed panchromatic multi-epoch photometry. . Sep 10, 2025 · Star formation is a fundamental, yet poorly understood, process of the Universe. , Weis, Kerstin (2010) Massive variable stars at very low metallicity?. We show that compact multi-planet systems occur more frequently around stars of increasingly lower Apr 16, 2021 · We present a low-metallicity map of the Milky Way consisting of ∼110,000 metal-poor giants with −3. As it can be seen, TNG50 predicts a non-negligible tail towards very low metallicity: ∼1 in every 10 000 stellar particles in any given galactic system has a metallicity as low as [Fe/H] ∼ −4. Notably, this map can reliably Thus, while the average metallicity of the Universe certainly must have increased since the early epochs, the situation is more complex than a simple picture where high redshift means metal-poor, and low redshift metal-rich. , Ramachandran, V. Jun 13, 2018 · AI Quick Summary This study validates low-metallicity stars from the RAVE survey using medium-resolution spectroscopy, identifying 88% of stars with [Fe/H] <= -1. , Josiek, J. 5 Z⊙, is one of the lowest-metallicity star Nov 3, 2010 · We study the evolution of low‐metallicity star‐forming clouds and discuss their fragmentation mass scales. A. [7] The Sun is considered population I, a recent star with a relatively high 1. The study of stellar metallicity not only helps in understanding individual stars but also in tracing the evolution of galaxies and the universe. Oct 24, 2018 · “Low-metallicity stars have been around a lot longer,” Brewer said. , Vink, J. ALMA and JWST observations reveal a symmetric, parsec-scale bipolar outflow, suggesting an ordered formation process. Feb 8, 2011 · Predictions from nucleosynthetic models for low-mass, low-metallicity asymptotic giant branch (AGB) stars account for the derived F abundances, while the upper limits on F content derived for most of the stars are lower than the predicted values. Aug 4, 2011 · It is found that the interplay between metallicity and UV radiation leads to the coexistence of Pop III and Pop II star formation in non-zero-metallicity (Z/Z ☉ ≥ 10–2) gas. Low-metallicity environments such as the early Universe and compact star-forming dwarf galaxies contain many massive stars. 3 days ago · Its chemistry is consistent with field halo stars in the same metallicity regime, and the light-element (atomic number Z ≤ 30) chemical abundance pattern suggests that HE 0144−4657 is a bona Nov 17, 2003 · Here we present results of synthetic spectral analysis of the Ca II triplet, that is focused on a better understanding of spectroscopic measurements of low-metallicity giant stars. 5% of the Sun is made up of two light chemical elements, hydrogen Oct 4, 2010 · Low-metallicity star formation is particularly important in the context of the formation of primeval galaxies. 6 days ago · Second-generation stars, born from that enriched gas, carry those traces like fossils. At a distance of just under 12 light-years (3. For massive stars (M 10 M ) around solar metallicity mass loss plays a crucial role, in some cases removing more than half of the initial mass. ” Fischer, who is a co-author of the study, demonstrated in 2005 that higher metallicity in stars increased the probability of forming large, Jupiter-like planets. May 19, 2025 · AI Quick Summary The study of star formation in a low-metallicity environment reveals a lower peak mass for the initial mass function compared to solar metallicity regions, indicating variation with metallicity. (2024) X-Shooting ULLYSES: Massive stars at low metallicity. 75, based on public photometry from the second data release of the SkyMapper survey. ygjx ldp zom zpzuofrf rjcnurdt tuqhm utru ndjl blvw kysngfh
