scholarly journals The effects of different Type Ia SN yields on Milky Way chemical evolution

2021 ◽  
Vol 503 (3) ◽  
pp. 3216-3231
Author(s):  
Marco Palla
Keyword(s):  
Chemical Evolution ◽  
White Dwarf ◽  
Time Distribution ◽  
Milky Way ◽  
Massive Stars ◽  
Abundance Patterns ◽  
Type Ia ◽  
Low Metallicity ◽  
Explosion Mechanism ◽  
Chemical Evolution Model

ABSTRACT We study the effect of different Type Ia SN nucleosynthesis prescriptions on the Milky Way chemical evolution. To this aim, we run detailed one-infall and two-infall chemical evolution models, adopting a large compilation of yield sets corresponding to different white dwarf progenitors (near-Chandrasekar and sub-Chandrasekar) taken from the literature. We adopt a fixed delay time distribution function for Type Ia SNe, in order to avoid degeneracies in the analysis of the different nucleosynthesis channels. We also combine yields for different Type Ia SN progenitors in order to test the contribution to chemical evolution of different Type Ia SN channels. The results of the models are compared with recent LTE and NLTE observational data. We find that ‘classical’ W7 and WDD2 models produce Fe masses and [α/Fe] abundance patterns similar to more recent and physical near-Chandrasekar and sub-Chandrasekar models. For Fe-peak elements, we find that the results strongly depend either on the white dwarf explosion mechanism (deflagration-to-detonation, pure deflagration, double detonation) or on the initial white dwarf conditions (central density, explosion pattern). The comparison of chemical evolution model results with observations suggests that a combination of near-Chandrasekar and sub-Chandrasekar yields is necessary to reproduce the data of V, Cr, Mn and Ni, with different fractions depending on the adopted massive stars stellar yields. This comparison also suggests that NLTE and singly ionized abundances should be definitely preferred when dealing with most of Fe-peak elements at low metallicity.

scholarly journals The contribution from rotating massive stars to the enrichment in Sr and Ba of the Milky Way

2019 ◽  
Author(s):  
F Rizzuti ◽  
G Cescutti ◽  
F Matteucci ◽  
A Chieffi ◽  
R Hirschi ◽  
...  
Keyword(s):  
Neutron Capture ◽  
Milky Way ◽  
Massive Stars ◽  
Rotational Velocity ◽  
Stellar Rotation ◽  
Deep Impact ◽  
Low Metallicity ◽  
Group Rotation ◽  
R Process ◽  
Chemical Evolution Model

Abstract Most neutron capture elements have a double production by r- and s-processes, but the question of production sites is complex and still open. Recent studies show that including stellar rotation can have a deep impact on nucleosynthesis. We studied the evolution of Sr and Ba in the Milky Way. A chemical evolution model was employed to reproduce the Galactic enrichment. We tested two different nucleosynthesis prescriptions for s-process in massive stars, adopted from the Geneva group and the Rome group. Rotation was taken into account, studying the effects of stars without rotation or rotating with different velocities. We also tested different production sites for the r-process: magneto rotational driven supernovae and neutron star mergers. The evolution of the abundances of Sr and Ba is well reproduced. The comparison with the the most recent observations shows that stellar rotation is a good assumption, but excessive velocities result in overproduction of these elements. In particular, the predicted evolution of the [Sr/Ba] ratio at low metallicity does not explain the data at best if rotation is not included. Adopting different rotational velocities for different stellar mass and metallicity better explains the observed trends. Despite the differences between the two sets of adopted stellar models, both show a better agreement with the data assuming an increase of rotational velocity toward low metallicity. Assuming different r-process sources does not alter this conclusion.

scholarly journals Heavy element evolution in the inner regions of the Milky Way

2020 ◽  
Vol 494 (4) ◽  
pp. 5534-5541 ◽  
Author(s):  
F Matteucci ◽  
A Vasini ◽  
V Grisoni ◽  
M Schultheis
Keyword(s):  
Heavy Element ◽  
Milky Way ◽  
Current Knowledge ◽  
Experiment Data ◽  
Stellar Nucleosynthesis ◽  
Abundance Patterns ◽  
Evolution Experiment ◽  
Element Evolution ◽  
Chemical Evolution Model ◽  
Detailed Chemical

ABSTRACT We present results for the evolution of the abundances of heavy elements (O, Mg, Al, Si, K, Ca, Cr, Mn, Ni, and Fe) in the inner Galactic regions (RGC ≤ 4 kpc). We adopt a detailed chemical evolution model already tested for the Galactic bulge and compare the results with Apache Point Observatory Galactic Evolution Experiment data. We start with a set of yields from the literature that are considered the best to reproduce the abundance patterns in the solar vicinity. We find that, in general, the predicted trends nicely reproduce the data but in some cases either the trend or the absolute values of the predicted abundances need to be corrected, even by large factors, in order to reach the best agreement. We suggest how the current stellar yields should be modified to reproduce the data and we discuss whether such corrections are reasonable in the light of the current knowledge of stellar nucleosynthesis. However, we also critically discuss the observations. Our results suggest that Si, Ca, Cr, and Ni are the elements for which the required corrections are the smallest, while for Mg and Al moderate modifications are necessary. On the other hand, O and K need the largest corrections to reproduce the observed patterns, a conclusion already reached for solar vicinity abundance patterns, with the exception of oxygen. For Mn, we apply corrections already suggested in previous works.

scholarly journals Observed Abundance Features and their Implications for Chemical Evolution

2004 ◽  
Vol 21 (2) ◽  
pp. 242-247
Author(s):  
Takuji Tsujimoto ◽  
Toshikazu Shigeyama
Keyword(s):  
Chemical Evolution ◽  
Globular Cluster ◽  
Milky Way ◽  
Galactic Halo ◽  
Cluster Formation ◽  
Abundance Trends ◽  
Nearby Galaxies ◽  
Star Formation Histories ◽  
Chemical Evolution Model ◽  
Shed Light

AbstractWe describe the star formation histories of the Milky Way dwarf spheroidal galaxy and the globular cluster ω Centauri in terms of an inhomogeneous chemical evolution model developed for the Galactic halo. The observed abundance trends seen in neutron-capture elements together with α-elements constrain our models to shed light on the histories of these nearby galaxies and ω Cen. The origin of low-α stars and a new picture of the globular cluster formation scenario induced by cloud–cloud collisions are also presented.

scholarly journals Galactic Chemical Evolution in the Context of the Recently Revealed SNe Ia Delay Time Distribution

2011 ◽  
Vol 7 (S281) ◽  
pp. 251-252
Author(s):  
Takuji Tsujimoto
Keyword(s):  
Chemical Evolution ◽  
Delay Time ◽  
Time Distribution ◽  
Chemical Properties ◽  
Thin Disk ◽  
Chemical Enrichment ◽  
Precise Knowledge ◽  
The Galaxy ◽  
Type Ia ◽  
Ia Supernovae

AbstractThe Galaxy is composed of four distinct structures, i.e., halo, bulge, and thick and thin disks, that are formed and evolved on different timescales; thus accordingly the speeds of chemical enrichment are different from one another, which is imprinted in individual stellar abundances. To decipher them, precise knowledge of the timing of the release of nucleosynthesis materials from various production sites is critical. The delay time distribution (DTD) of Type Ia supernovae (SNe Ia), recently revealed by the SNe Ia surveys of external galaxies, is incorporated into the models of chemical evolution for each structure. Here we report that the observed chemical properties for the thin and thick disks are compatible with a new SNe Ia DTD, and suggests a close chemical connection between the two in the way that the thin disk is formed from gas left after thick disk formation. This nicely explains the lack of thin disk stars with [Fe/H] ≲ −0.8. In this new context, a top-heavy IMF for the bulge is firmly confirmed. Finally we discuss the possibility of some modification of the DTD that might be considered for the halo case.

scholarly journals Supernova Yields for Chemical Evolution Modeling

2013 ◽  
Vol 9 (S298) ◽  
pp. 154-166
Author(s):  
Ken'ichi Nomoto ◽  
Tomoharu Suzuki
Keyword(s):  
Chemical Evolution ◽  
Massive Stars ◽  
Elemental Abundance ◽  
Solar Abundance ◽  
Abundance Pattern ◽  
Chemical Enrichment ◽  
Abundance Patterns ◽  
Yield Table ◽  
Supernova Explosions ◽  
Evolution Modeling

AbstractWe review the recent results of the nucleosynthesis yields of massive stars. We examine how those yields are affected by some hydrodynamical effects during the supernova explosions, namely, explosion energies from those of hypernovae to faint supernovae, mixing and fallback of processed materials, asphericity, etc. Those parameters in the supernova nucleosynthesis models are constrained from observational data of supernovae and metal-poor stars. The elemental abundance patterns observed in extremely metal-poor stars show some peculiarities relative to the solar abundance pattern, which suggests the important contributions of hypernovae and faint supernovae in the early chemical enrichment of galaxies. These constraints on supernova nucleosynthesis are taken into account in the latest yield table for chemical evolution modeling.

scholarly journals Observational constraints on the origin of the elements

2020 ◽  
Vol 635 ◽  
pp. A38 ◽  
Author(s):  
P. Eitner ◽  
M. Bergemann ◽  
C. J. Hansen ◽  
G. Cescutti ◽  
I. R. Seitenzahl ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Globular Clusters ◽  
Local Thermodynamic Equilibrium ◽  
Galactic Chemical Evolution ◽  
Galactic Disc ◽  
Milky Way Galaxy ◽  
Halo Stars ◽  
Type Ia ◽  
Low Metallicity ◽  
Different Sources

The abundance ratios of manganese to iron in late-type stars across a wide metallicity range place tight constraints on the astrophysical production sites of Fe-group elements. In this work, we investigate the chemical evolution of Mn in the Milky Way galaxy using high-resolution spectroscopic observations of stars in the Galactic disc and halo stars, as well as a sample of globular clusters. Our analysis shows that local thermodynamic equilibrium (LTE) leads to a strong imbalance in the ionisation equilibrium of Mn I and Mn II lines. Mn I produces systematically (up to 0.6 dex) lower abundances compared to the Mn II lines. Non-LTE (NLTE) radiative transfer satisfies the ionisation equilibrium across the entire metallicity range, of −3 ≲ [Fe/H] ≲ −1, leading to consistent abundances from both ionisation stages of the element. We compare the NLTE abundances with Galactic Chemical Evolution models computed using different sources of type Ia and type II supernova (SN Ia and SN II) yields. We find that a good fit to our observations can be obtained by assuming that a significant (∼75%) fraction of SNe Ia stem from a sub-Chandrasekhar (sub-Mch) channel. While this fraction is larger than that found in earlier studies (∼50%), we note that we still require ∼25% near-Mch SNe Ia to obtain solar [Mn/Fe] at [Fe/H] = 0. Our new data also suggest higher SN II Mn yields at low metallicity than typically assumed in the literature.

scholarly journals On the origin of nitrogen at low metallicity

2021 ◽  
Vol 502 (3) ◽  
pp. 4359-4376
Author(s):  
Arpita Roy ◽  
Michael A Dopita ◽  
Mark R Krumholz ◽  
Lisa J Kewley ◽  
Ralph S Sutherland ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Massive Stars ◽  
High Redshift ◽  
Large Scatter ◽  
Abundance Distribution ◽  
Abundance Patterns ◽  
M 10 ◽  
Low Metallicity ◽  
Formation Efficiency

ABSTRACT Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at high redshift, since most observational calibrations of O/H implicitly depend upon the intrinsic N/O ratio. The observed N/O ratio, however, shows large scatter at low O/H, and is strongly dependent on galactic environment. We show that several heretofore unexplained features of the N/O distribution at low O/H can be explained by the N seen in metal-poor galaxies being mostly primary nitrogen that is returned to the ISM via pre-supernova winds from rapidly rotating massive stars (M ≳ 10 M⊙, v/vcrit ≳ 0.4). This mechanism naturally produces the observed N/O plateau at low O/H. We show that the large scatter in N/O at low O/H also arises naturally from variations in star-formation efficiency. By contrast, models in which the N and O come primarily from supernovae provide a very poor fit to the observed abundance distribution. We propose that the peculiar abundance patterns we observe at low O/H are a signature that dwarf galaxies retain little of their SN ejecta, leaving them with abundance patterns typical of winds.

scholarly journals 2D chemical evolution model: The impact of Galactic disc asymmetries on azimuthal chemical abundance variations

2019 ◽  
Vol 628 ◽  
pp. A38 ◽  
Author(s):  
E. Spitoni ◽  
G. Cescutti ◽  
I. Minchev ◽  
F. Matteucci ◽  
V. Silva Aguirre ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
Density Fluctuations ◽  
Evolution Model ◽  
Galactic Disc ◽  
Chemical Abundance ◽  
Oxygen Abundance ◽  
External Galaxies ◽  
The Impact ◽  
Chemical Evolution Model

Context. Galactic disc chemical evolution models generally ignore azimuthal surface density variation that can introduce chemical abundance azimuthal gradients. Recent observations, however, have revealed chemical abundance changes with azimuth in the gas and stellar components of both the Milky Way and external galaxies. Aims. Our aim is to quantify the effects of spiral arm density fluctuations on the azimuthal variations of the oxygen and iron abundances in disc galaxies. Methods. We developed a new 2D Galactic disc chemical evolution model that is capable of following not just radial but also azimuthal inhomogeneities. Results. The density fluctuations resulting from a Milky Way-like N-body disc formation simulation produce azimuthal variations in the oxygen abundance gradients of the order of 0.1 dex. Moreover, the azimuthal variations are more evident in the outer Galactic regions, which is in agreement with the most recent observations in external galaxies. Using a simple analytical model, we show that the largest fluctuations with azimuth result near the spiral structure co-rotation resonance where the relative speed between the spiral and gaseous disc is the slowest. Conclusion. We provide a new 2D chemical evolution model capable of following azimuthal density variations. Density fluctuations extracted from a Milky Way-like dynamical model lead to a scatter in the azimuthal variations of the oxygen abundance gradient, which is in agreement with observations in external galaxies. We interpret the presence of azimuthal scatter at all radii by the presence of multiple spiral modes moving at different pattern speeds, as found in both observations and numerical simulations.

Sign in / Sign up

Export Citation Format

Share Document