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Artigos de revistas sobre o tema "Stars of low metallicity"

Autor: Grafiati

Publicado: 8 de junho de 2024

Última modificação: 31 de julho de 2025

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1

Pakmor, Rüdiger, Christine M. Simpson, Freeke van de Voort, et al. "Formation and fate of low-metallicity stars in TNG50." Monthly Notices of the Royal Astronomical Society 512, no. 3 (2022): 3602–15. http://dx.doi.org/10.1093/mnras/stac717.

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ABSTRACT Low-metallicity stars give rise to unique spectacular transients and are of immense interest for understanding stellar evolution. 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. 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. Because low-metallicity stars are difficult to observe directly, cosmological simulations are cruci

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2

Hirschi, Raphael, Cristina Chiappini, Georges Meynet, André Maeder, and Sylvia Ekström. "Stellar Evolution at Low Metallicity." Proceedings of the International Astronomical Union 3, S250 (2007): 217–30. http://dx.doi.org/10.1017/s1743921308020528.

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AbstractMassive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this review, we first recall the effect of metallicity (Z) on the evolution of massive stars. We then describe the strong impact of rotation induced mixing and mass loss at very low Z. The strong mixing leads to a significant production of primary 14N, 13C and 22Ne. Mass loss during the red supergiant stage allows the production of Wolf-Rayet stars, type Ib,c supernovae and possibly gamma

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3

Sabach, Efrat. "Jsolated Stars of Low Metallicity." Galaxies 6, no. 3 (2018): 89. http://dx.doi.org/10.3390/galaxies6030089.

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We study the effects of a reduced mass-loss rate on the evolution of low metallicity Jsolated stars, following our earlier classification for angular momentum (J) isolated stars. By using the stellar evolution code MESA we study the evolution with different mass-loss rate efficiencies for stars with low metallicities of Z = 0 . 001 and Z = 0 . 004 , and compare with the evolution with solar metallicity, Z = 0 . 02 . We further study the possibility for late asymptomatic giant branch (AGB)—planet interaction and its possible effects on the properties of the planetary nebula (PN). We find for al

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4

Bouret, J. C., T. Lanz, F. Martins, et al. "Massive stars at low metallicity." Astronomy & Astrophysics 555 (June 18, 2013): A1. http://dx.doi.org/10.1051/0004-6361/201220798.

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Hirschi, R. "Very low-metallicity massive stars:." Astronomy & Astrophysics 461, no. 2 (2006): 571–83. http://dx.doi.org/10.1051/0004-6361:20065356.

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6

Karakas, Amanda I., Maria Lugaro, and Simon W. Campbell. "The slow-neutron capture process in low-metallicity asymptotic giant branch stars." Proceedings of the International Astronomical Union 5, S265 (2009): 57–60. http://dx.doi.org/10.1017/s1743921310000165.

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AbstractElements heavier than iron are produced in asymptotic giant branch (AGB) stars via the slow neutron capture process (s process). Recent observations of s-process-enriched Carbon Enhanced Metal-Poor (CEMP) stars have provided an unprecedented wealth of observational constraints on the operation of the s-process in low-metallicity AGB stars. We present new preliminary full network calculations of low-metallicity AGB stars, including a comparison to the composition of a few s-process rich CEMP stars. We also discuss the possibility of using halo planetary nebulae as further probes of low-

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7

Garcia, Miriam, Artemio Herrero, Francisco Najarro, et al. "Low-metallicity (sub-SMC) massive stars." Proceedings of the International Astronomical Union 12, S329 (2016): 313–21. http://dx.doi.org/10.1017/s1743921317003088.

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AbstractThe double distance and metallicity frontier marked by the SMC has been finally broken with the aid of powerful multi-object spectrographs installed at 8-10m class telescopes. VLT, GTC and Keck have enabled studies of massive stars in dwarf irregular galaxies of the Local Group with poorer metal-content than the SMC. The community is working to test the predictions of evolutionary models in the low-metallicity regime, set the new standard for the metal-poor high-redshift Universe, and test the extrapolation of the physics of massive stars to environments of decreasing metallicity. In t

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8

Martayan, Christophe, Dietrich Baade, Juan Zorec, Yves Frémat, Juan Fabregat, and Sylvia Ekström. "Massive Oe/Be stars at low metallicity: candidate progenitors of long GRBs?" Proceedings of the International Astronomical Union 6, S272 (2010): 300–301. http://dx.doi.org/10.1017/s1743921311010660.

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AbstractAt low metallicity B-type stars rotate faster than at higher metallicity, typically in the SMC. As a consequence, a larger number of fast rotators is expected in the SMC than in the Galaxy, in particular more Be/Oe stars. With the ESO-WFI in its slitless mode, we examined the SMC open clusters and found an occurence of Be stars 3 to 5 times larger than in the Galaxy. The evolution of the angular rotational velocity seems to be the main key on the understanding of the specific behaviour and stellar evolution of such stars at different metallicities. With the results of this WFI study an

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9

Bomans, Dominik J., and Kerstin Weis. "Massive variable stars at very low metallicity?" Proceedings of the International Astronomical Union 6, S272 (2010): 265–70. http://dx.doi.org/10.1017/s1743921311010519.

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AbstractObservational contraints on the evolution and instabilities of massive stars at very low metallicities are limited. Most of the information come from HST observations of one target, I Zw 18. Recent distance estimates of I Zw 18 put it at 17 Mpc, moving detailed studies of single stars clearly beyond the range of current ground based telescopes. Since massive stars with metallcities of 1/10 of solar and below are our best proxies for massive stars in (proto-) galaxies around the time of reionization, finding them and studying their evolution and instabilities is of premium importance fo

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10

Omukai, Kazuyuki. "Formation of Very Low-metallicity Stars." Proceedings of the International Astronomical Union 18, S361 (2022): 521–27. http://dx.doi.org/10.1017/s1743921322002988.

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AbstractI 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.

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11

Heap, Sara R., and Thierry Lanz. "Effects of Rotation in Low-Metallicity Stars." Symposium - International Astronomical Union 215 (2004): 220–21. http://dx.doi.org/10.1017/s0074180900195580.

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We have carried out a spectral analysis of 17 O-type stars in the Small Magellanic Cloud (SMC). We find several lines of evidence that rotation plays an important role in massive stars in this low-metallicity galaxy (Z=0.2 Z⊙): (1) strong enrichment of nitrogen in half the program stars due to rotational mixing of processed material in the core up to the surface; (2) reduction of the effective gravity by the centrifugal force; (3) apparent anomalies in cluster isochrones that imply some stars are rotating at critical velocities.

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12

Yang, Ming, Alceste Z. Bonanos, Biwei Jiang, et al. "Evolved massive stars at low-metallicity." Astronomy & Astrophysics 647 (March 2021): A167. http://dx.doi.org/10.1051/0004-6361/202039596.

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We present a case study in which we used a novel method to identify red supergiant (RSG) candidates in NGC 6822 based on their 1.6 μm H-bump. We collected 32 bands of photometric data for NGC 6822 ranging from the optical to the mid-infrared, derived from Gaia, PS1, LGGS, VHS, UKIRT, IRSF, HAWK-I, Spitzer, and WISE. Using the theoretical spectra from MARCS, we demonstrate that there is a prominent difference around 1.6 μm (H-bump) between targets with high and low surface gravity (HSG and LSG). Taking advantage of this feature, we identify efficient color–color diagrams of rzH (r − z vs. z − H

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13

Bonifacio, P. "Low Metallicity Stars in our Galaxy." EAS Publications Series 24 (2007): 251–61. http://dx.doi.org/10.1051/eas:2007034.

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Yang, Ming, Alceste Z. Bonanos, Bi-Wei Jiang, et al. "Evolved massive stars at low-metallicity." Astronomy & Astrophysics 629 (September 2019): A91. http://dx.doi.org/10.1051/0004-6361/201935916.

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We present a clean, magnitude-limited (IRAC1 or WISE1 ≤ 15.0 mag) multiwavelength source catalog for the Small Magellanic Cloud (SMC) with 45 466 targets in total, with the purpose of building an anchor for future studies, especially for the massive star populations at low-metallicity. The catalog contains data in 50 different bands including 21 optical and 29 infrared bands, retrieved from SEIP, VMC, IRSF, AKARI, HERITAGE, Gaia, SkyMapper, NSC, Massey (2002, ApJS, 141, 81), and GALEX, ranging from the ultraviolet to the far-infrared. Additionally, radial velocities and spectral classification

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15

Yang, Ming, Alceste Z. Bonanos, Bi-Wei Jiang, et al. "Evolved massive stars at low metallicity." Astronomy & Astrophysics 639 (July 2020): A116. http://dx.doi.org/10.1051/0004-6361/201937168.

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We present the most comprehensive red supergiant (RSG) sample for the Small Magellanic Cloud (SMC) to date, including 1239 RSG candidates. The initial sample was derived based on a source catalog for the SMC with conservative ranking. Additional spectroscopic RSGs were retrieved from the literature, and RSG candidates were selected based on the inspection of Gaia and 2MASS color-magnitude diagrams (CMDs). We estimate that there are in total ∼1800 or more RSGs in the SMC. We purify the sample by studying the infrared CMDs and the variability of the objects, though there is still an ambiguity be

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16

Kubátová, B., D. Szécsi, A. A. C. Sander, et al. "Low-metallicity massive single stars with rotation." Astronomy & Astrophysics 623 (February 25, 2019): A8. http://dx.doi.org/10.1051/0004-6361/201834360.

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Context. Metal-poor massive stars are assumed to be progenitors of certain supernovae, gamma-ray bursts, and compact object mergers that might contribute to the early epochs of the Universe with their strong ionizing radiation. However, this assumption remains mainly theoretical because individual spectroscopic observations of such objects have rarely been carried out below the metallicity of the Small Magellanic Cloud. Aims. Here we explore the predictions of the state-of-the-art theories of stellar evolution combined with those of stellar atmospheres about a certain type of metal-poor (0.02

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17

Iwamoto, N., T. Kajino, G. J. Mathews, and M. Y. Fujimoto. "Nucleosynthesis in low-mass, low-metallicity AGB stars." Nuclear Physics A 719 (May 2003): C57—C60. http://dx.doi.org/10.1016/s0375-9474(03)00958-8.

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18

Pols, O. R., R. G. Izzard, M. Lugaro, and S. E. de Mink. "Modelling the evolution and nucleosynthesis of carbon-enhanced metal-poor stars." Proceedings of the International Astronomical Union 4, S252 (2008): 383–89. http://dx.doi.org/10.1017/s1743921308023260.

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AbstractWe present the results of binary population simulations of carbon-enhanced metal-poor (CEMP) stars. We show that nitrogen and fluorine are useful tracers of the origin of CEMP stars, and conclude that the observed paucity of very nitrogen-rich stars puts strong constraints on possible modifications of the initial mass function at low metallicity. The large number fraction of CEMP stars may instead require much more efficient dredge-up from low-metallicity asymptotic giant branch stars.

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19

Heap, Sara. "Role of massive stars in the evolution of primitive galaxies." Proceedings of the International Astronomical Union 10, H16 (2012): 370. http://dx.doi.org/10.1017/s1743921314011429.

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AbstractAn important factor controlling galaxy evolution is feedback from massive stars. It is believed that the nature and intensity of stellar feedback changes as a function of galaxy mass and metallicity. At low mass and metallicity, feedback from massive stars is mainly in the form of photoionizing radiation. At higher mass and metallicity, it is in stellar winds. I Zw 18 is a local blue, compact dwarf galaxy that meets the requirements for a primitive galaxy: low halo mass <109M⊙, strong photoionizing radiation, no galactic outflow, and very low metallicity, log(O/H)+12=7.2. We will de

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20

Sharina, M. E., L. N. Makarova, and D. I. Makarov. "Population gradients in dwarf spheroidal galaxies KKs 3 and ESO 269-66." Proceedings of the International Astronomical Union 14, S344 (2018): 420–21. http://dx.doi.org/10.1017/s1743921318005550.

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AbstractWe compare the properties of stellar populations for globular clusters (GCs) and field stars in two dwarf spheroidal galaxies (dSphs): ESO269-66, a close neighbour of NGC5128, and KKs3, one of the few isolated dSphs within 10 Mpc. We analyse the surface density profiles of low and high metallicity (blue and red) stars in two galaxies using the Sersic law. We argue that 1) the density profiles of red stars are steeper than those of blue stars, which evidences in favour of the metallicity and age gradients in dSphs; 2) globular clusters in KKs3 and ESO 269-66 contain 4 and 40 percent of

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21

Garcia, Miriam. "Observations of Very Low-Metallicity Massive Stars." Proceedings of the International Astronomical Union 18, S361 (2022): 36–45. http://dx.doi.org/10.1017/s174392132200312x.

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AbstractVery metal-poor massive stars hold the key to interpret high-redshift star-forming galaxies and the early reionization epoch, but also contemporary events such as gravitational waves. To study these objects in resolved environments, we need to resort to dwarf irregular galaxies far from the potential wells of M31 and the Milky Way, and therefore distant. While the archives, recently boosted by the ULLYSES and XSHOOTU programs, store a healthy dataset of massive stars in the Milky Way and the Magellanic Clouds, the number of observed targets with poorer metal content than the SMC (1/5 Z

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22

Thielemann, Friedrich-K., Khalil Farouqi, Stephan Rosswog, and Karl-Ludwig Kratz. "r-Process Contributions to Low-Metallicity Stars." EPJ Web of Conferences 260 (2022): 09002. http://dx.doi.org/10.1051/epjconf/202226009002.

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Various nucleosynthesis studies have pointed out that the rapid neutron capture r-process elements in very metal-poor (VMP) halo stars might have different origins. It has been known that an r-process can either be obtained in neutron-rich low Ye conditions or in high entropy environments [see e.g. 1–5], an overview over many investigations has appeared recently [6]. In the present article we analyze with statistical methods the observational abundance patterns from trans-Fe elements up to the actinides and come to the conclusion that four to ﬁve categories of astrophysical events must have co

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Kubátová, Brankica. "Low-metallicity massive single stars with rotation." ASTRONOMICAL JOURNAL OF AZERBAIJAN, no. 02 (2024): 6. https://doi.org/10.59849/2078-4163.2024.2.6.

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Szécsi, Dorottya, Norbert Langer, Sung-Chul Yoon, et al. "Low-metallicity massive single stars with rotation." Astronomy & Astrophysics 581 (August 25, 2015): A15. http://dx.doi.org/10.1051/0004-6361/201526617.

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Meynet, Georges, Nolan R. Walborn, Ian Hunter, et al. "Evolution of Massive Stars at Low Metallicity." Proceedings of the International Astronomical Union 3, S250 (2007): 571–76. http://dx.doi.org/10.1017/s1743921308020954.

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AbstractThis paper reports the contributions made on the occasion of the Special Session entitled “Evolution of Massive Stars at Low Metallicity” which was held on Sunday, December 9, 2007 in Kauai (USA).

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Tolstoy, Eline, Giuseppina Battaglia, and Andrew Cole. "Stars at Low Metallicity in Dwarf Galaxies." Proceedings of the International Astronomical Union 4, S255 (2008): 310–17. http://dx.doi.org/10.1017/s174392130802499x.

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AbstractDwarf galaxies offer an opportunity to understand the properties of low metallicity star formation both today and at the earliest times at the epoch of the formation of the first stars. Here we concentrate on two galaxies in the Local Group: the dwarf irregular galaxy Leo A, which has been the recent target of deep HST/ACS imaging (Cole et al. 2007) and the Sculptor dwarf spheroidal, which has been the target of significant wide field spectroscopy with VLT/FLAMES (Battaglia 2007).

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Iwamoto, Nobuyuki, Toshitaka Kajino, Grant J. Mathews, Masayuki Y. Fujimoto, and Wako Aoki. "s-Process Nucleosynthesis in Low-Metallicity Stars." Journal of Nuclear Science and Technology 39, sup2 (2002): 554–57. http://dx.doi.org/10.1080/00223131.2002.10875161.

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D'Orazi, V., S. Randich, E. Flaccomio, F. Palla, G. G. Sacco, and R. Pallavicini. "Metallicity of low-mass stars in Orion." Astronomy & Astrophysics 501, no. 3 (2009): 973–83. http://dx.doi.org/10.1051/0004-6361/200811241.

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Matsuura, M., G. C. Sloan, J. Bernard-Salas, et al. "Carbon-rich AGB stars in our Galaxy and nearby galaxies as possible sources of PAHs." Proceedings of the International Astronomical Union 4, S251 (2008): 197–200. http://dx.doi.org/10.1017/s1743921308021558.

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AbstractWe have obtained infrared spectra of carbon-rich AGB stars in three nearby galaxies – the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal galaxy. Our primary aim is to investigate gas compositions and mass-loss rate of these stars as a function of metallicity, by comparing AGB stars in several galaxies with different metallicities. C2H2are detectable from AGB stars, and possibly PAHs are subsequently formed from C2H2. Thus, it is worth investigating chemical processes at low metallicity. These stars were observed using the Infrared Spectrometer (irs) onboard theSpitz

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Sahlholdt, Christian L., Sofia Feltzing, and Diane K. Feuillet. "Characterizing epochs of star formation across the Milky Way disc using age–metallicity distributions of GALAH stars." Monthly Notices of the Royal Astronomical Society 510, no. 4 (2021): 4669–88. http://dx.doi.org/10.1093/mnras/stab3681.

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ABSTRACT We provide a detailed map of the ages and metallicities of turn-off stars in the Milky Way disc based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age–metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way. In the first phase, inner disc stars form along a single age–metallicity sequence and are today kinematically hot. The end of this phase is marked by a local minimum in the inner disc age distribution 10 Gyr ago. At this time, we find the stellar popu

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Aoki, Wako, Timothy C. Beers, Takuma Suda, Satoshi Honda, and Young Sun Lee. "Very Low-Mass Stars with Extremely Low Metallicity in the Milky Way's Halo." Proceedings of the International Astronomical Union 11, S317 (2015): 45–50. http://dx.doi.org/10.1017/s174392131500959x.

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AbstractLarge surveys and follow-up spectroscopic studies in the past few decades have been providing chemical abundance data for a growing number of very metal-poor ([Fe/H] <−2) stars. Most of them are red giants or main-sequence turn-off stars having masses near 0.8 solar masses. Lower mass stars with extremely low metallicity ([Fe/H] <−3) are yet to be explored. Our high-resolution spectroscopic study for very metal-poor stars found with SDSS has identified four cool main-sequence stars with [Fe/H] <−2.5 among 137 objects (Aoki et al. 2013). The effective temperatures of these star

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Patra, Sudeshna, Jessy Jose, and Neal J. Evans II. "Does Metallicity Affect the Protoplanetary Disk Fraction? Answers from the Outer Milky Way." Astrophysical Journal 970, no. 1 (2024): 88. http://dx.doi.org/10.3847/1538-4357/ad4996.

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Abstract The role of metallicity in shaping protoplanetary disk evolution remains poorly comprehended. This study analyzes the disk fraction of 10 young (0.9–2.1 Myr) and low-metallicity (0.34–0.83 Z ⊙) clusters located in the outer Milky Way with Galactocentric distances between 10 and 13 kpc. Using JHK data obtained from UKIDSS, the calculated disk fraction values for low-mass stars (0.2–2 M ⊙) ranged from 42% to 7%. To enhance the statistical reliability of our analysis, eight additional low-metallicity clusters are sourced from previous studies with metallicity range 0.25–0.85 Z ⊙ along wi

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Whitten, D. D., V. M. Placco, T. C. Beers, et al. "J-PLUS: Identification of low-metallicity stars with artificial neural networks using SPHINX." Astronomy & Astrophysics 622 (February 2019): A182. http://dx.doi.org/10.1051/0004-6361/201833368.

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Context. We present a new methodology for the estimation of stellar atmospheric parameters from narrow- and intermediate-band photometry of the Javalambre Photometric Local Universe Survey (J-PLUS), and propose a method for target pre-selection of low-metallicity stars for follow-up spectroscopic studies. Photometric metallicity estimates for stars in the globular cluster M15 are determined using this method. Aims. By development of a neural-network-based photometry pipeline, we aim to produce estimates of effective temperature, Teff, and metallicity, [Fe/H], for a large subset of stars in the

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Hallakoun, Na’ama, and Dan Maoz. "A bottom-heavy initial mass function for the likely-accreted blue-halo stars of the Milky Way." Monthly Notices of the Royal Astronomical Society 507, no. 1 (2021): 398–413. http://dx.doi.org/10.1093/mnras/stab2145.

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ABSTRACT We use Gaia DR2 to measure the initial mass function (IMF) of stars within 250 pc and masses in the range of 0.2 &lt; m/M⊙ &lt; 1.0, separated according to kinematics and metallicity, as determined from Gaia transverse velocity, vT, and location on the Hertzsprung–Russell diagram (HRD). The predominant thin-disc population (vT &lt; 40 km s−1) has an IMF similar to traditional (e.g. Kroupa) stellar IMFs, with star numbers per mass interval dN/dm described by a broken power law, m−α, and index $\alpha _\textrm {high}=2.03^{+0.14}_{-0.05}$ above m ∼ 0.5, shallowing to $\alpha

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Tanaka, Kei E. I., Jonathan C. Tan, Yichen Zhang, and Takashi Hosokawa. "Multiple Feedback in Low-Metallicity Massive Star Formation." Proceedings of the International Astronomical Union 14, S344 (2018): 190–94. http://dx.doi.org/10.1017/s1743921318005549.

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AbstractWe theoretically investigate the impact of feedback and its metallicity dependence in massive star formation from prestellar cores at all metallicity range. We include the feedback by MHD disk winds, radiation pressure, and photoevaporation solving the evolution of protostars and accretion flows self-consistently. Interestingly, we find that the feedback does not set the upper mass limit of stellar birth mass at any metallicity. At the solar metallicity, the MHD disk wind is the dominant feedback to set the star formation efficiencies (SFEs) from the prestellar cores similar to low-mas

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Wang, Shu, Xiaodian Chen, Jianxing Zhang, and Licai Deng. "Double-mode RR Lyrae star — robust distance and metallicity indicators." Proceedings of the International Astronomical Union 18, S376 (2022): 275–80. http://dx.doi.org/10.1017/s1743921323003186.

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AbstractRR Lyrae (RR Lyr) stars are a well-known and useful distance indicator for old stellar populations such as globular clusters and dwarf galaxies. Fundamental-mode RR Lyr (RRab) stars are commonly used to measure distances, and the accuracy of the determined distance is strongly constrained by metallicity. Here, we investigate the metallicity dependence in the period–luminosity (PL) relation of double-mode RR Lyr (RRd) stars. We find and establish a linear relation between metallicity and period or period ratio for RRd stars. This relation can predict the metallicity as accurately as the

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Maldonado, J., E. Villaver, C. Eiroa, and G. Micela. "Connecting substellar and stellar formation: the role of the host star’s metallicity." Astronomy & Astrophysics 624 (April 2019): A94. http://dx.doi.org/10.1051/0004-6361/201833827.

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Context. Most of our current understanding of the planet formation mechanism is based on the planet metallicity correlation derived mostly from solar-type stars harbouring gas-giant planets. Aims. To achieve a more extensive grasp on the substellar formation process, we aim to analyse in terms of their metallicity a diverse sample of stars (in terms of mass and spectral type) covering the whole range of possible outcomes of the planet formation process (from planetesimals to brown dwarfs and low-mass binaries). Methods. Our methodology is based on the use of high-precision stellar parameters d

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Szécsi, Dorottya, and Norbert Langer. "The Life and Death of Massive Stars in the Starburst Galaxy I Zw 18." Proceedings of the International Astronomical Union 11, A29B (2015): 215–16. http://dx.doi.org/10.1017/s1743921316004968.

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AbstractMassive stars at low metallicity are strong candidates for two of the most energetic explosions in the Universe: long duration gamma-ray bursts and superluminous supernovae. But what is the reason these explosions prefer low metallicity environments? To answer this question, we investigate how massive stellar evolution proceeds in low metallicity environments.

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Alonso-Santiago, J., A. Marco, I. Negueruela, et al. "NGC 3105: a young open cluster with low metallicity." Astronomy & Astrophysics 616 (August 2018): A124. http://dx.doi.org/10.1051/0004-6361/201833073.

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Context. NGC 3105 is a young open cluster hosting blue, yellow, and red supergiants. This rare combination makes it an excellent laboratory for constraining evolutionary models of high-mass stars. It has been poorly studied, and the fundamental parameters such as its age or distance are not well defined. Aims. We intend to characterise in an accurate way the cluster and its evolved stars, for which we derive for the first time atmospheric parameters and chemical abundances. Methods. We performed a complete analysis combining UBVR photometry with spectroscopy. We obtained spectra with classific

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Lattanzio, John C. "Carbon dredge-up in low-mass stars and solar metallicity stars." Astrophysical Journal 344 (September 1989): L25. http://dx.doi.org/10.1086/185522.

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Robert, Carmelle. "Ultraviolet spectral libraries of massive stars at low metallicity." Symposium - International Astronomical Union 193 (1999): 616–17. http://dx.doi.org/10.1017/s0074180900206463.

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Three new ultraviolet spectral libraries of massive, hot stars using high and medium resolution spectra of objects located in the solar neighbourhood and the Magellanic Clouds are presented. Massive stars display unique wind signatures which are relatively easy to study in the ultraviolet. These libraries are crucial tools when investigating the massive stellar population of distant star-forming galaxies.

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Lanfranchi, Gustavo A., and Francesca Matteucci. "Stellar metallicity distributions in local dwarf spheroidal galaxies: a comparison between model and observations." Proceedings of the International Astronomical Union 5, S262 (2009): 370–71. http://dx.doi.org/10.1017/s1743921310003273.

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AbstractWe analyze the main populations of 6 local Dwarf Spheroidal Galaxies by comparing the observed stellar metallicity distributions with the predictions of chemical evolution models. The predicted metallicity distributions of stars generally exhibit a low range of metallicities, a peak below the one of the MW disc in the solar neighborhood (but similar to the Halo), and a sharp decrease at higher metallicities in agreement with observations. The position of the peak is related to the low star formation rates adopted whereas the sharp decrease is a consequence of the occurrence of strong g

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Go, Minsung, Myoungwon Jeon, Yumi Choi, et al. "Understanding Stellar Mass–Metallicity and Size Relations in Simulated Ultrafaint Dwarf Galaxies." Astrophysical Journal 986, no. 2 (2025): 214. https://doi.org/10.3847/1538-4357/add2fa.

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Abstract Reproducing the physical characteristics of ultrafaint dwarf galaxies (UFDs) in cosmological simulations is challenging, particularly with respect to stellar metallicity and galaxy size. To investigate these difficulties in detail, we conduct high-resolution simulations (M gas ∼ 60 M ⊙, M DM ∼ 300 M ⊙) on six UFD analogs (M vir ∼ 108–109 M ⊙, M ⋆ ∼ 103–2.1 × 104 M ⊙ at z = 0). Our findings reveal that the stellar properties of the UFD analogs are shaped by diverse star-forming environments from multiple progenitor halos in the early Universe. Notably, our UFD analogs exhibit a better

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Stancliffe, Richard J., George C. Angelou, and John C. Lattanzio. "Lithium production by thermohaline mixing in low-mass, low-metallicity asymptotic giant branch stars." Proceedings of the International Astronomical Union 5, S268 (2009): 405–10. http://dx.doi.org/10.1017/s1743921310004539.

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AbstractWe examine the effects of thermohaline mixing on the composition of the envelopes of low-metallicity asymptotic giant branch (AGB) stars. We have evolved models of 1, 1.5 and 2M⊙ and of metallicity Z = 10−4 from the pre-main sequence to the end of the thermal pulsing asymptotic giant branch with thermohaline mixing applied throughout the simulations. We find that the small amount of 3He that remains after the first giant branch is enough to drive thermohaline mixing on the AGB and that the mixing is most efficient in the early thermal pulses, with the efficiency dropping from pulse to

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Beers, Timothy C., Deokkeun An, Jennifer A. Johnson, et al. "Metallicity Mapping with gri Photometry: The Virgo Overdensity and the Halos of the Galaxy." Proceedings of the International Astronomical Union 5, S262 (2009): 127–30. http://dx.doi.org/10.1017/s1743921310002644.

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AbstractWe describe the methodology required for estimation of photometric estimates of metallicity based on the SDSS gri passbands, which can be used to probe the properties of main-sequence stars beyond ~10 kpc, complementing studies of nearby stars from more metallicity-sensitive color indices that involve the u passband. As a first application of this approach, we determine photometric metal abundance estimates for individual main-sequence stars in the Virgo Overdensity, which covers almost 1000 deg2 on the sky, based on a calibration of the metallicity sensitivity of stellar isochrones in

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Placco, Vinicius M., Timothy C. Beers, Rafael M. Santucci, et al. "Spectroscopic Validation of Low-metallicity Stars from RAVE." Astronomical Journal 155, no. 6 (2018): 256. http://dx.doi.org/10.3847/1538-3881/aac20c.

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Engelbrecht, Chris, Refilwe Kgoadi, and Fabio Frescura. "A search for low-metallicity pulsating B stars." EPJ Web of Conferences 152 (2017): 01019. http://dx.doi.org/10.1051/epjconf/201715201019.

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Sana, H., F. Tramper, M. Abdul-Masih, et al. "X-Shooting ULLYSES: Massive stars at low metallicity." Astronomy & Astrophysics 688 (August 2024): A104. http://dx.doi.org/10.1051/0004-6361/202347479.

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Context. 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. Using the medium-resolution spectrograph X-shooter, spectra of 235 OB and Wolf-Rayet (WR) stars in subsolar metallicity environments have been secured. The bulk of the targets belong to the Large and Small Magellanic Clouds, with the exception of three stars in NGC 3109 and Sextans A. Aims. This second paper in the series focuses on the optical observations of Magellanic Clouds targets. It

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Ventura, P., F. D'Antona, and I. Mazzitelli. "Yields from low metallicity, intermediate mass AGB stars:." Astronomy & Astrophysics 393, no. 1 (2002): 215–23. http://dx.doi.org/10.1051/0004-6361:20021001.

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Witzke, V., T. Reinhold, A. I. Shapiro, N. A. Krivova, and S. K. Solanki. "Effect of metallicity on the detectability of rotational periods in solar-like stars." Astronomy & Astrophysics 634 (February 2020): L9. http://dx.doi.org/10.1051/0004-6361/201936608.

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The accurate determination of stellar rotation periods is important for estimating stellar ages and for understanding stellar activity and evolution. While rotation periods can be determined for about thirty thousand stars in the Kepler field, there are over one hundred thousand stars, especially with low photometric variability and irregular pattern of variations, for which rotational periods are unknown. Here we investigate the effect of metallicity on the detectability of rotation periods. This is done by synthesising light curves of hypothetical stars that are identical to our Sun with the

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