نتایج جستجو برای: very poor

تعداد نتایج: 879884  

Journal: :The Astrophysical Journal 2022

Abstract We place empirical constraints on the yields from zero- and low-metallicity core-collapse supernovae (CCSNe) using abundances measured in very metal-poor (VMP; [Fe/H] ≤ −2) damped Ly α absorbers (DLAs). For some abundance ratios ([N,Al,S/Fe]), VMP DLAs constrain metal of first SNe more reliably than stars. compile a large sample high-S/N over 30 yr literature, most with high-resolution...

Journal: :Monthly Notices of the Royal Astronomical Society 2021

ABSTRACT We evaluate the rotational velocity of stars observed by Pristine survey towards Galactic anticentre spanning a wide range metallicities from extremely metal-poor regime ([Fe/H] < ?3) to nearly solar metallicity. In direction, (V?) is similar tangential in galactic longitude direction (V?). This allows us estimate V? Gaia early data release 3 (Gaia EDR3) proper motions for witho...

Journal: :The Astrophysical Journal 2021

Ancient, very metal-poor stars offer a window into the earliest epochs of galaxy formation and assembly. We combine data from H3 Spectroscopic Survey Gaia to measure metallicities, abundances $\alpha$ elements, stellar ages, orbital properties sample 482 (VMP; [Fe/H]$<-2$) in order constrain their origins. This is confined $1\lesssim |Z| \lesssim3$ kpc Galactic plane. find that >70% VMP near di...

Journal: :Publications of the Astronomical Society of Japan 2022

Silicon and Strontium are key elements to explore the nucleosynthesis chemical evolution of Galaxy by measurements very metal-poor stars. There are, however, only a few useful spectral lines these in optical range that measurable for such low-metallicity Here we report on abundances two determined from near-infrared high-resolution spectra obtained with Subaru Telescope Infrared Doppler instrum...

Journal: :Astronomy and Astrophysics 2022

Context. In recent observations of extremely metal-poor, low-mass, starburst galaxies, almost solar Fe/O ratios are reported, despite N/O consistent with the low metallicity. Aims. We aim to investigate if peculiar can be a distinctive signature an early enrichment produced by very massive objects dying as pair-instability supernova (PISN). Methods. ran chemical evolution models yields that acc...

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