scholarly journals Metallicity gradients in the Milky Way

2009 ◽  
Vol 5 (S265) ◽  
pp. 317-324 ◽  
Author(s):  
Walter J. Maciel ◽  
Roberto D. D. Costa
Keyword(s):  
Chemical Evolution ◽  
Time Variation ◽  
Milky Way ◽  
Spiral Galaxies ◽  
Hii Regions ◽  
Theoretical Models ◽  
Open Clusters ◽  
Observational Constraints ◽  
B Stars ◽  
The Past

AbstractRadial metallicity gradients are observed in the disks of the Milky Way and in several other spiral galaxies. In the case of the Milky Way, many objects can be used to determine the gradients, such as HII regions, B stars, Cepheids, open clusters and planetary nebulae. Several elements can be studied, such as oxygen, sulphur, neon, and argon in photoionized nebulae, and iron and other elements in cepheids, open clusters and stars. As a consequence, the number of observational characteristics inferred from the study of abundance gradients is very large, so that in the past few years they have become one of the main observational constraints of chemical evolution models. In this paper, we present some recent observational evidences of abundance gradients based on several classes of objects. We will focus on (i) the magnitude of the gradients, (ii) the space variations, and (iii) the evidences of a time variation of the abundance gradients. Some comments on recent theoretical models are also given, in an effort to highlight their predictions concerning abundance gradients and their variations.

scholarly journals Age-Metallicity Relation: Comparison of Open Clusters' Data with Stellar Populations

1996 ◽  
Vol 171 ◽  
pp. 351-351
Author(s):  
Giovanni Carraro ◽  
Yuen K. Ng
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
Past History ◽  
Stellar Populations ◽  
Open Clusters ◽  
Galactic Disc ◽  
The Past ◽  
History Of

The age–metallicity relation (AMR) from the Old Open Clusters population (Carraro & Chiosi, 1994; Friel & Janes, 1993) is compared with the disc stellar populations obtained from a recently developed model of the Milky Way by Ng 1994. A picture for the chemical evolution of the disc is presented in which the presence of a newly discovered Bar population (t = 8–9 Gyr, Z = 0.005–0.030) is taken into account. We suggest that the past history of the Galactic Disc has been significantly influenced by infall of metal poor gas from the halo and accretion events. The results are shown in Fig. 1.

scholarly journals Abundance gradients from Planetary Nebulae in the galactic disk

1997 ◽  
Vol 180 ◽  
pp. 397-404 ◽  
Author(s):  
W.J. Maciel
Keyword(s):  
Chemical Evolution ◽  
Spiral Galaxies ◽  
Galactic Disk ◽  
Chemical Elements ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
Additional Constraint ◽  
Established Fact ◽  
Metallicity Distribution

Radial abundance gradients in the disks of spiral galaxies are made evident from observations of ionized nebulae (HII regions, planetary nebulae, and SNRs) and stars. They have been observed for several chemical elements, and their presence is an established fact, despite some inconsistencies in the results. Therefore, these gradients can be considered as an additional constraint to the chemical evolution models, as the age-metallicity relation or the metallicity distribution of the G-dwarfs.

scholarly journals A Comparison of Chemical Evolution between the Milky Way and M31 Galaxy

2006 ◽  
Vol 2 (S235) ◽  
pp. 313-313
Author(s):  
J. Yin ◽  
J.L. Hou ◽  
R.X. Chang ◽  
S. Boissier ◽  
N. Prantzos
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Milky Way ◽  
Local Group ◽  
Spiral Galaxies ◽  
Star Formation History ◽  
Milky Way Galaxy ◽  
Andromeda Galaxy ◽  
Formation History ◽  
Formation And Evolution

Andromeda galaxy (M31,NGC224) is the biggest spiral in the Local Group. By studying the star formation history(SFH) and chemical evolution of M31, and comparing with the Milky Way Galaxy, we are able to understand more about the formation and evolution of spiral galaxies.

The evolution of the Milky Way’s radial metallicity gradient as seen by APOGEE, CoRoT, and Gaia

2018 ◽  
Vol 14 (A30) ◽  
pp. 257-257
Author(s):  
Friedrich Anders ◽  
Ivan Minchev ◽  
Cristina Chiappini
Keyword(s):  
Milky Way ◽  
Past History ◽  
Open Clusters ◽  
Dynamical Models ◽  
Giant Stars ◽  
The Past ◽  
The Status ◽  
History Of ◽  
Abundance Profile ◽  
Red Giant

AbstractThe time evolution of the radial metallicity gradient is one of the most important constraints for Milky Way chemical and chemo-dynamical models. In this talk we reviewed the status of the observational debate and presented a new measurement of the age dependence of the radial abundance gradients, using combined asteroseismic and spectroscopic observations of red giant stars. We compared our results to state-of-the-art chemo-dynamical Milky Way models and recent literature results obtained with open clusters and planetary nebulae, and propose a new method to infer the past history of the Galactic radial abundance profile.

scholarly journals High-mass stars in Milky Way clusters

2016 ◽  
Vol 12 (S329) ◽  
pp. 271-278
Author(s):  
Ignacio Negueruela
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Theoretical Models ◽  
Open Clusters ◽  
High Mass ◽  
Mass Star ◽  
Formation And Evolution

AbstractYoung open clusters are our laboratories for studying high-mass star formation and evolution. Unfortunately, the information that they provide is difficult to interpret, and sometimes contradictory. In this contribution, I present a few examples of the uncertainties that we face when confronting observations with theoretical models and our own assumptions.

Structure and evolution of metallicity and age radial profiles in Milky-Way-like galaxies

2018 ◽  
Vol 14 (A30) ◽  
pp. 284-284
Author(s):  
E. Athanassoula
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
Spiral Galaxies ◽  
Short Summary ◽  
Radial Profiles

AbstractI will give here a very short summary of some of the work I have been doing lately on the chemical evolution in Milky-Way-like spiral galaxies.

scholarly journals The Gaia-ESO Survey: The N/O abundance ratio in the Milky Way

2018 ◽  
Vol 618 ◽  
pp. A102 ◽  
Author(s):  
L. Magrini ◽  
F. Vincenzo ◽  
S. Randich ◽  
E. Pancino ◽  
G. Casali ◽  
...  
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Milky Way ◽  
Open Cluster ◽  
Abundance Ratio ◽  
Open Clusters ◽  
Spatially Resolved ◽  
Wide Range ◽  
The Galaxy ◽  
Formation Efficiency

Context. The abundance ratio N/O is a useful tool to study the interplay of galactic processes, for example star formation efficiency, timescale of infall, and outflow loading factor. Aims. We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare this ratio with a set of chemical evolution models to understand the role of infall, outflow, and star formation efficiency in the building up of the Galactic disc. Methods. We used the abundances from IDR2-3, IDR4, IDR5 data releases of the Gaia-ESO Survey both for Galactic field and open cluster stars. We determined membership and average composition of open clusters and we separated thin and thick disc field stars. We considered the effect of mixing in the abundance of N in giant stars. We computed a grid of chemical evolution models, suited to reproduce the main features of our Galaxy, exploring the effects of the star formation efficiency, infall timescale, and differential outflow. Results. With our samples, we map the metallicity range −0.6 ≤ [Fe/H] ≤ 0.3 with a corresponding −1.2 ≤ log(N/O) ≤ −0.2, where the secondary production of N dominates. Thanks to the wide range of Galactocentric distances covered by our samples, we can distinguish the behaviour of log(N/O) in different parts of the Galaxy. Conclusions. Our spatially resolved results allow us to distinguish differences in the evolution of N/O with Galactocentric radius. Comparing the data with our models, we can characterise the radial regions of our Galaxy. A shorter infall timescale is needed in the inner regions, while the outer regions need a longer infall timescale, coupled with a higher star formation efficiency. We compare our results with nebular abundances obtained in MaNGA galaxies, finding in our Galaxy a much wider range of log(N/O) than in integrated observations of external galaxies of similar stellar mass, but similar to the ranges found in studies of individual H II regions.

scholarly journals Evolution of lithium in the Milky Way halo, discs, and bulge

2019 ◽  
Vol 489 (3) ◽  
pp. 3539-3546 ◽  
Author(s):  
V Grisoni ◽  
F Matteucci ◽  
D Romano ◽  
X Fu
Keyword(s):  
Chemical Evolution ◽  
Spectroscopic Data ◽  
Binary Systems ◽  
Milky Way ◽  
Theoretical Models ◽  
Model Predictions ◽  
The Galaxy ◽  
Formation Efficiency ◽  
Detailed Chemical ◽  
Milky Way Halo

Abstract In this work, we study the Galactic evolution of lithium by means of chemical evolution models in the light of the most recent spectroscopic data from Galactic stellar surveys. We consider detailed chemical evolution models for the Milky Way halo, discs, and bulge, and we compare our model predictions with the most recent spectroscopic data for these different Galactic components. In particular, we focus on the decrease of lithium at high metallicity observed by the AMBRE Project, the Gaia-ESO Survey, and other spectroscopic surveys, which still remains unexplained by theoretical models. We analyse the various lithium producers and confirm that novae are the main source of lithium in the Galaxy, in agreement with other previous studies. Moreover, we show that, by assuming that the fraction of binary systems giving rise to novae is lower at higher metallicity, we can suggest a novel explanation to the lithium decline at super-solar metallicities: the aforementioned assumption is based on independent constraints on the nova system birth rate, which have been recently proposed in the literature. As regards the thick disc, it is less lithium enhanced due to the shorter time-scale of formation and higher star formation efficiency with respect to the thin disc; therefore, we have a faster evolution and the ‘reverse knee’ in the A(Li) versus [Fe/H] relation is shifted towards higher metallicities. Finally, we present our predictions about lithium evolution in the Galactic bulge, which, however, still need further data to be confirmed or disproved.

scholarly journals Abundance gradients: tracing the chemical properties of the disk

2009 ◽  
Vol 5 (H15) ◽  
pp. 790-790
Author(s):  
Roberto D.D. Costa ◽  
Walter J. Maciel
Keyword(s):  
Time Evolution ◽  
Chemical Evolution ◽  
Galactic Disk ◽  
Chemical Properties ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
B Stars ◽  
Radial Gradient ◽  
The Galaxy ◽  
Vertical Gradients

AbstractAbundance gradients are key parameters to constrain the chemical evolution of the galactic disk. In this review recent determinations for the radial gradient are described, including its slope as derived from different objects such as planetary nebulae, HII regions, cepheids, or B stars, and for different elements. Inner and outer limits for the radial gradient, as well as its time evolution, both related to the chemical evolution of the Galaxy, are also described. The possible existence of azimuthal and vertical gradients is also discussed.

The GOTHAM survey: chemical evolution of Milky Way globular clusters

2017 ◽  
Vol 13 (S334) ◽  
pp. 25-28
Author(s):  
Bruno Dias ◽  
Beatriz Barbuy ◽  
Ivo Saviane ◽  
Enrico V. Held ◽  
Gary Da Costa ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Stellar Population ◽  
Milky Way ◽  
Open Clusters ◽  
Giant Stars ◽  
Globular Cluster System ◽  
Galactic Globular Clusters ◽  
Red Giant

AbstractMilky Way globular clusters are excellent laboratories for stellar population detailed analysis that can be applied to extragalactic environments with the advent of the 40m-class telescopes like the ELT. The globular cluster population traces the early evolution of the Milky Way which is the field of Galactic archaeology. We present our GlObular clusTer Homogeneous Abundance Measurement (GOTHAM) survey. We derived radial velocities, Teff, log(g), [Fe/H], [Mg/Fe] for red giant stars in one third of all Galactic globular clusters that represent well the Milky Way globular cluster system in terms of metallicity, mass, reddening, and distance. Our method is based on low-resolution spectroscopy and is intrinsically reddening free and efficient even for faint stars. Our [Fe/H] determinations agree with high-resolution results to within 0.08 dex. The GOTHAM survey provides a new metallicity scale for Galactic globular clusters with a significant update of metallicities higher than [Fe/H] > -0.7. We show that the trend of [Mg/Fe] with metallicity is not constant as previously found, because now we have more metal-rich clusters. Moreover, peculiar clusters whose [Mg/Fe] does not match Galactic stars for a given metallicity are discussed. We also measured the CaII triplet index for all stars and we show that the different chemical evolution of Milky Way open clusters, field stars, and globular clusters implies different calibrations of calcium triplet to metallicity.

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