Low metallicity. ; Monelli, M. We study the influence of low levels of metal enrichment on the cool...

Low metallicity. ; Monelli, M. We study the influence of low levels of metal enrichment on the cooling and collapse of initially ionized gas in small protogalactic halos using three-dimensional, smoothed particle hydrodynamics simulations with particle During this meeting, we will discuss: How are low-metallicity environments, including both local and high-redshift galaxies, different from their metal-rich counterparts? How does low-metallicity impact stellar and/or AGN feedback? What are the sources producing high-ionization nebular emission? In low-metallicity gas, the higher accretion rate and lower opacity result in weaker feedback and then higher up-per mass limit. Understanding the metallicity of stars and galaxies is essential for studying their formation, structure, and dynamics. Oct 1, 2002 · The MacDonald solar metallicity isochrones in Fig. 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. Objects with high and low metallicities are found at all redshifts. 22 for wind velocities was incorporated, suggesting a mass-loss dependence of Z^0. Feb 2, 2024 · The aim of this work was to study the physical properties and the nucleosynthesis of zero and very low-metallicity massive stars as a function of the initial rotation velocity, finding, if possible, the minimum metallicity, which allows a significant production of the elements heavier than the Fe-peak elements. Apr 8, 2025 · This study examines a low-metallicity PDR in the N13 region of the Small Magellanic Cloud (SMC) where we spatially resolve the ionization front, the H 2 dissociation front, and the C/CO transition using 12CO J=2-1, 3-2 and [CI] (1-0) observations from the Atacama Large Millimeter/sub-mm Array (ALMA) and near-infrared spectroscopy of the H 2 2. 265-270 doi:10. 3 days ago · It has been proposed that this occurs when effective metal line cooling occurs at a metallicity threshold of Z/Z > 10−3. Feb 25, 2009 · We have calculated Fe and Ti abundances in 12 low-metallicity main sequence M stars using high-resolution spectra. 12 hours ago · Unlike typical stellar streams, C-19 is a rare and significant find due to its extraordinarily low metallicity, below -3. Abstract. 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. The XShootU project aims to obtain ground-based optical to near-infrared spectroscopy of all targets observed by the Hubble Space Telescope (HST) under the Director's Discretionary program ULLYSES. Weisz, Kareem El-Badry, Jan Henneco, Alessandro Savino, Meredith Durbin, Yumi Choi, Roger E. Olivier, Bren E. , Weis, Kerstin (2010) Massive variable stars at very low metallicity?. A streamlined platform for accessing astrophysics data and research resources. JWST reveals TOI-5293 A b’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. 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. Cole, Matteo Correnti Apr 10, 2024 · The gas-phase metallicity is derived exploiting a revisited version of the calibrations presented in Curti et al. Jun 22, 2023 · Left: average radial light-weighted stellar metallicity profile of the Milky Way (black and grey) in comparison with those of low-redshift Milky Way-mass star-forming galaxies in the MaNGA survey Aug 1, 2022 · This review summarizes our understanding of early-type dwarfs, which are the end-points of the evolution of low-mass galaxies. Vink, Jorick S. 4. 75, based on public photometry from the second data release of the SkyMapper survey. 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 Jan 10, 2025 · Low-metallicity molecular clouds in the Milky Way and nearby galaxies exhibit a strong deficiency in turbulent support against their self-gravity, suggesting that the magnetic field may play a Jan 10, 2022 · Discovering Low Metallicity Stellar Structures In a recent discovery, it now turns out that our galaxy, the Milky Way, is hot to a stellar structure that is unique because it is made of stars with Nov 14, 2023 · Download a PDF of the paper titled Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?, by Zhen Yuan and 13 other authors 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. If you don't know of our interstellar visitor by now, here is a brief recap. Only later supernovae, planetary nebulae and neutron star mergers enriched the universe with heavier elements. ; Larsen, S. This result confirms the trend that metallicity evolution becomes more significant toward lower stellar masses, in keeping with a downsizing scenario where low-mass galaxies evolve onto the local MZ relation at later cosmic times. 1 day ago · This suggests it coalesced around a star with very low “metallicity” – meaning it contained fewer elements heavier than hydrogen and helium. Jul 1, 2025 · These anomalies suggest that GCs experienced self-enrichment processes early in their formation, likely driven by feedback from a first population of stars. Astronomy & Astrophysics, 603. The early universe had a low content of elements heavier than helium and formed stars and brown dwarfs with lower metallicity. Mass loss plays a dominant role in the evolution of massive stars at solar metallicity. We do not detect significant HF absorption (∼2 σ) and derive a conservative 5 σ upper limit of . ; Battaglia, G. The first stellar generations are different from solar metallicity stars due to their low metal content or absence of it. The metallicity of stellar populations in the Milky Way galaxy is a key indicator of the different stages of galactic chemical enrichment over time. Jun 3, 2025 · A Low Metallicity Massive Contact Binary Star System Candidate in WLM Identified by Hubble and James Webb Space Telescope Imaging Maude Gull, Daniel R. Lithium is not detected, suggesting a low-metallicity extension of the previously Feb 19, 2019 · We find anomalously low-metallicity (ALM) gas in 10% of the star-forming spaxels and in 25% of the galaxies in the sample. Using the medium-resolution spectrograph X-shooter, spectra of 235 OB and Wolf-Rayet (WR) stars in subsolar metallicity environments have been secured. 3 match the data quite well, and are excellent for the low-metallicity case. (2019) for two similarly low-mass z ∼ 2 galaxies, which also show extremely high emission-line equivalent widths and which have gradients of ∼0. Notably, this map can reliably Apr 8, 2025 · This study examines a low-metallicity PDR in the N13 region of the Small Magellanic Cloud (SMC) where we spatially resolve the ionization front, the H 2 dissociation front, and the C/CO transition using 12CO J=2-1, 3-2 and [CI] (1-0) observations from the Atacama Large Millimeter/sub-mm Array (ALMA) and near-infrared spectroscopy of the H 2 2. Our models at Z = 10−8 show that stars more massive than about 60 M⊙ may lose a significant fraction of their initial mass in the red The first stellar generations are different from solar metallicity stars due to their low metal content or absence of it. Believe of it like a first-generation star system, born shortly after the Big Bang when the universe was still relatively pristine. Cohen, Andrew A. Although the super-solar isochrones achieve good agreement with the data for MV > 6, stars more luminous than this appear to be hotter than the models (by ∼ 200 K). The low metallicity of subdwarfs is coupled with their old age. 5% of the Sun is made up of two light chemical elements, hydrogen 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. The stream’s low metallicity, combined with the spur feature, suggests a possible dual origin: a globular cluster or a dwarf galaxy. 2018: Slow cooling in low-metallicity clouds: an origin of globular cluster bimodality?Monthly Notices of the Royal Astronomical Society 479 (1): 200-210 Beasley, M. (2017) Wolf-Rayet spin at low metallicity and its implication for black hole formation channels. 10 hours ago · Star-forming gas in galaxy centers, or in X-ray clusters with a deep potential well, typically reaches near-solar or super-solar metallicities, while the CGM can exhibit a wider range down to 10 3 Z ⊙ due to low-metallicity accretion and incomplete recycling of galactic outflows. This extremely low metallicity places it among the most chemically ancient stars known outside the Milky Way. Understanding the chemistry of the interstellar medium in low-metallicity environments is cru-cial to unveil physical and chemical processes in the past Galactic environment or those in high-redshift galaxies, where the metallicity was significantly lower compared to the present-day solar neighborhood. Jan 1, 2006 · Stellar Evolution at Low Metallicity Stellar Evolution at Low Metallicity Mass Loss, Explosions, Cosmology : Proceedings of a Meeting Held in Tartu, Estonia, 15-19 August 2005 - Astronomical Society of the Pacific Conference Series Henny J. M Lamers 1st Edition Book (01 Jan 2006) 6 days ago · The mechanism of strange metallicity remains difficult to understand. 45 Z⊙. 3 dex for Jul 9, 2018 · This is the definition of metallic character as the term is used in chemistry. The study calls for further investigations using ultraviolet mass-loss diagnostics for OB stars with weak winds and/or low luminosities. Jun 13, 2018 · This study validates low-metallicity stars from the RAVE survey using medium-resolution spectroscopy, identifying 88% of stars with [Fe/H] <= -1. Now it is shown that in a strongly correlated d-orbital kagome metal, compact orbitals created by destructive interference can Results. 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. 98. L. 5 for luminous O stars. After discussing different mass loss mechanisms and their metallicity dependence, we present the possibility of strong mass loss at very low metallicity. doi:10. Mar 18, 2025 · View a PDF of the paper titled Low-Metallicity Star Formation Survey in Sh2-284 (LZ-STAR). Aug 31, 2011 · This shows that low-mass stars can be formed at very low metallicity, that is, below the critical value of Z. (2020b) (which are anchored to the Te abundance scale), refined using a sample of local, metal-poor galaxies to better sample the low-metallicity regime. ; Bryan, G. 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. It will provide binary fractions and orbital configurations of binary systems and search for dormant black hole binary candidates (OB+BH). Our grid can be used to interpret observations of local star-forming dwarf galaxies and high-redshift galaxies, as well as the metal-poor components of our Milky Way and its globular clusters. I. Cleri, Grace M. A. Metallic character versus metallicity is discussed. Proceedings of the International Astronomical Union, 6. . Specifically, understanding when, where, and at what rate metal-poor stars form throughout cosmic time is critical to many active topics of research. Low-metallicity stars are generally older and have a higher proportion of hydrogen and helium, while high-metallicity stars are younger and have a greater abundance of heavier elements. Apr 16, 2021 · We present a low-metallicity map of the Milky Way consisting of ∼110,000 metal-poor giants with −3. The STScI 2026 Spring Symposium aims to advance our understanding of the low-metallicity Universe by bringing together researchers from the stellar, local galaxy, and high-redshift communities to examine the role of low metallicity from nearby stars and galaxies, through cosmic noon, to the epoch of reionization and cosmic dawn. Low metallicity objects, such as Population II stars, are typically found in older stellar populations and have lower metal content. Galaxy evolution scenarios suggest three pathways to form an XMP: (1) secular evolution at low galaxy masses, (2) slow evolution in voids, or (3) dilution of measured abundances from infall of pristine gas. Aug 17, 2018 · It is necessary, however, to increase the number of the lowest-metallicity BCDs to make better primordial helium abundances measurements; to study the low-mass and low-luminosity regimes that these metal-deficient galaxies define; and to better understand the physical and chemical evolution of these systems. This is also important for the understanding of the diversity of the chemical Oct 16, 2023 · Download a PDF of the paper titled Modeling molecular hydrogen in low metallicity galaxies, by Ava Polzin and 3 other authors Mar 16, 2020 · The environmental differences caused by the deceased metallicity would lead to a different chemical history of star- and planet-forming regions in the LMC and other low-metallicity galaxies. S. 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. H. The old subdwarfs belong therefore often to the older structures in our Milky Way, mainly the 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. We would like to show you a description here but the site won’t allow us. 0, including 306 CEMP candidates, and confirming transverse velocities as a selection criterion for low-metallicity candidates. Oct 10, 2008 · We study the influence of low levels of metal enrichment on the cooling and collapse of initially ionized gas in small protogalactic halos using three-dimensional, smoothed particle hydrodynamics Tau Ceti fits the second category, given its similar mass and low variability, but relative lack of metals. 1051/0004-6361/201730503 JWST reveals TOI-5293 A b’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. Source of ionization and C-IV emission in I Zw 18, by Dorottya Sz\'ecsi and 7 other authors Aug 31, 2011 · This shows that low-mass stars can be formed at very low metallicity, that is, below the critical value of Z. On July 1 last year, the Asteroid Terrestrial-impact Last Alert System detected an object racing through JWST reveals TOI-5293 A b’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. 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. First, low-Z stars are more compact (see Fig. 35 (~1/20 Zsun). Oct 31, 2025 · Similar Papers Found 4 papers Optical Strong Line Ratios Cannot Distinguish Between Stellar Populations and Accreting Black Holes at High Ionization Parameters and Low Metallicities Nikko J. 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 Article: Supernova dust formation and the grain growth in the early universe: the critical metallicity for low-mass star formation Fernandez, R. Their primeval stellar populations provide a unique laboratory for Aug 12, 2021 · We therefore conclude that low-level image features may provide reliable cues for the robust perception of metallicity. Conclusions. Oct 4, 2010 · Low-metallicity star formation is particularly important in the context of the formation of primeval galaxies. 1) due to lower opacity. Bomans, Dominik J. 9. 2019: An old, metal-poor globular cluster in Sextans a and the Aug 17, 2018 · It is necessary, however, to increase the number of the lowest-metallicity BCDs to make better primordial helium abundances measurements; to study the low-mass and low-luminosity regimes that these metal-deficient galaxies define; and to better understand the physical and chemical evolution of these systems. Hot core chemistry in the LMC should provide us with useful information to understand chemical complexity in the past metal-poor universe. In this work, we revise the current description of metal and dust evolution in the ISM of local low-metallicity dwarf galaxies and develop a new description of Lyman-break galaxies (LBGs) which are considered to be their high-redshift counterparts in terms of star formation, stellar mass, and metallicity. Ordered massive star formation in the outer Galaxy, by Yu Cheng and 7 other authors 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 Jun 26, 2025 · View a PDF of the paper titled Low-metallicity massive single stars with rotation. Mar 14, 2022 · Low metallicity stars give rise to unique spectacular transients and are of immense interest for understanding stellar evolution. 8 hours ago · Spectroscopic measurements show that the star contains only about one-forty-thousandth of the Sun ’s iron abundance. Nov 23, 2025 · In astronomy, metallicity is commonly classified into three main categories: low metallicity, intermediate metallicity, and high metallicity. We have compared the evolution of mechanical luminosity and momentum injection for low-metallicity models to that predicted by the classical, Z⊙ feedback paradigm. 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. G. It is clear that models constructed with lower metallicities do not match the Sun well: they have shallow CZs and low CZ helium abundances as well. Jul 11, 2018 · Unfortunately for the sun itself (and future life on Earth), low-metallicity stars burn fuel faster than high-metallicity stars, so our sun would die about a billion years sooner than we thought. Our calibration can now be used to determine metallicity to within ± 0. The recently discovered XMP galaxy Leoncino Apr 8, 2025 · AI Quick Summary This paper explores how dust coagulation within vortices can form planetesimals in low metallicity environments, proposing a feedback loop where vortex trapping enhances dust concentration, which in turn boosts vortex trapping and dust growth. Moreover, the formation of low metallicity stars is intricately linked to galaxy evolution The mass-metallicity relation evolves from high-redshift (bottom) to low-redshift (top). 0 dex. Apr 10, 2024 · The gas-phase metallicity is derived exploiting a revisited version of the calibrations presented in Curti et al. At the same time, its atmosphere displays strong carbon enhancement relative to iron. Understanding the sources of this chemical enrichment requires detailed models of stellar nucleosynthesis and mass loss, particularly for stars at low metallicity (Z). Mar 25, 2020 · Extremely metal-poor (XMP) galaxies are low-mass, star-forming galaxies with gas-phase oxygen abundances below 12+log (O/H) = 7. These subdwarf and extreme-subdwarf stars allow us to extend our calibration of a method to determine cool-dwarf-star metallicities using molecular band strength indices from low-resolution spectra. 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 JWST reveals TOI-5293Ab’s low-metallicity atmosphere and inflated radius, highlighting the challenges of studying planets around variable red dwarfs. 1017 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. Feb 19, 2019 · We find anomalously low-metallicity (ALM) gas in 10% of the star-forming spaxels and in 25% of the galaxies in the sample. Nov 21, 2023 · At low metallicity, stellar winds are weak, and the more massive stars fail to explode as core-collapse SNe. The study finds this mechanism more effective than the streaming instability, especially in low metallicity and across the entire disk 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. This chemical combination provides clear evidence that the gas from which the Mar 18, 2025 · The study provides a comprehensive analysis of clumped winds in low-metallicity environments, offering insights into mass loss of massive stars and refining empirical mass-loss rate constraints. We present projected rotational velocities (v sin i) of all sources, and, using 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). The bulk of the targets belong to the 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. Massive star evolution at low metallicity is shown to differ qualitatively from that in metal-rich environments. Oct 18, 2022 · The positive metallicity gradient in GLASS-Zgrad1 is even steeper than those measured by Wang et al. 3 days ago · Low metallicity stars are typically hotter and more massive than high metallicity stars, leading to differences in their evolution and eventual fate. 1 dex/kpc. This upper limit decreases with increasing metallicity gradually without remarkable sudden drops. In addition to this trend, more massive galaxies show some kind of saturation. Older generations of stars formed in a metal-poor early stage of the Universe, so it follows that they have lower metallicities than younger generations of stars which formed in a more metal-rich Universe. Mar 16, 2022 · Low-metallicity stars are the focus of many studies in stellar astrophysics and cosmology. Lithium is not detected, suggesting a low-metallicity extension of the previously May 24, 2022 · Mass–metallicity relation of RESOLVE and ECO SEL galaxies, showing that almost all SF-AGN (blue squares) are low-metallicity SEL dwarfs with a median metallicity of 0. May 28, 2024 · Explore the significance of stellar metallicity, its impact on star evolution, galactic patterns, and the role it plays in the formation of planets and galaxies. ; Leaman, R. 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. The effect of metallicity on opacities affects solar structure, and a comparison of models constructed with different heavy-element abundances but otherwise identical physics is shown in Fig. ; Pedreros, M. ; Gallart, C. 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. \\textbf{By making use of advanced stellar evolution models generated by the Geneva Stellar Evolution Code (GENEC Jan 29, 2025 · An empirical metallicity dependence of Z^0. High-metallicity stars like the Sun, for example, at an intermediate location between the low-metallicity galactic halo and the high-radiation galactic center, may be scattered throughout the galaxy, affecting the definition of the galactic habitable zone. The incidence rate of ALM gas increases strongly with both global and local measures of the specific star formation rate and is higher in lower mass galaxies and in the outer regions of galaxies. Oct 16, 2023 · Download a PDF of the paper titled Modeling molecular hydrogen in low metallicity galaxies, by Ava Polzin and 3 other authors Context. 5 < [Fe/H] < −0. 5. 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. Backhaus et al. Aims. 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). The similarities have inspired popular culture references for decades, [citation needed] as well as scientific examination. , Harries, Tim J. III. wymv ztzzbpm jpejnz mctuo ckqpj gqn spzs xgvy adyy xqbk