The role of AGB stars in the evolution of globular clusters

2018 ◽  
Vol 14 (S343) ◽  
pp. 291-300
Author(s):  
Paolo Ventura ◽  
Franca D’Antona ◽  
Marcella Di Criscienzo ◽  
Flavia Dell’Agli ◽  
Marco Tailo
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Globular Clusters ◽  
State Of The Art ◽  
High Resolution Spectroscopy ◽  
Agb Stars ◽  
Light Elements ◽  
Original Population ◽  
Traditional Paradigm

AbstractThe results from high-resolution spectroscopy and accurate photometry have challenged the traditional paradigm that stars in globular clusters (GC) are simple stellar populations, rather suggesting that these structures harbor distinct groups of stars, differing in the chemical composition, particularly in the abundances of the light elements, from helium to silicon. Because this behavior is not shared by field stars, it is generally believed that some self-enrichment mechanism must have acted in GC, such that new stellar generations formed from the ashes of stars belonging to the original population. In this review, after presenting the state-of-the-art of the observations of GC stars, we discuss the possibility that the pollution of the intra-cluster medium was provided by the winds of AGB stars of initial mass above ∼3 M⊙. These objects evolve with time scales of 40 − 100 Myr and contaminate their surroundings with gas processed by p-capture nucleosynthesis, in agreement with the chemical patterns traced by GC stars.

scholarly journals CALCIUM AND LIGHT-ELEMENTS ABUNDANCE VARIATIONS FROM HIGH-RESOLUTION SPECTROSCOPY IN GLOBULAR CLUSTERS

2010 ◽  
Vol 712 (1) ◽  
pp. L21-L25 ◽  
Author(s):  
Eugenio Carretta ◽  
Angela Bragaglia ◽  
Raffaele Gratton ◽  
Sara Lucatello ◽  
Michele Bellazzini ◽  
...  
Keyword(s):  
High Resolution ◽  
Globular Clusters ◽  
High Resolution Spectroscopy ◽  
Light Elements

scholarly journals The Voyage of Metals in the Universe from Cosmological to Planetary Scales: the need for a Very High-Resolution, High Throughput Soft X-ray Spectrometer

2021 ◽  
Author(s):  
F. Nicastro ◽  
J. Kaastra ◽  
C. Argiroffi ◽  
E. Behar ◽  
S. Bianchi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Deep Understanding ◽  
High Resolution Spectroscopy ◽  
X Ray ◽  
Viable Solution ◽  
Surrounding Space ◽  
Nuclear Processes ◽  
The Universe ◽  
Very High

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.

scholarly journals Chemical analysis of NGC 6528: one of the most metal-rich bulge globular clusters

2018 ◽  
Vol 620 ◽  
pp. A96 ◽  
Author(s):  
C. Muñoz ◽  
D. Geisler ◽  
S. Villanova ◽  
I. Saviane ◽  
C. C. Cortés ◽  
...  
Keyword(s):  
High Resolution ◽  
Chemical Analysis ◽  
Iron Content ◽  
Globular Clusters ◽  
Chemical Characterization ◽  
Heavy Elements ◽  
High Resolution Spectroscopy ◽  
Origin And Evolution ◽  
Red Giant ◽  
Good Agreement

Context. The bulge globular clusters (GCs) are key tracers of the bulge, a central and ancient component of our Galaxy. It is essential to understand their formation and evolution to study that of the bulge, as well as their relationship with the other Galactic GC systems (halo and disk GCs). High-resolution spectroscopy is a powerful tool for such studies, allowing us to obtain a detailed chemical characterization and kinematics of the clusters and to compare their chemical patterns with those of their halo and disk counterparts. Aims. Our main goals are to obtain detailed abundances for a sample of seven red giant members of NGC 6528 in order to characterize their chemical composition and study the relationship of this GC with the bulge, and with other bulge, halo, and disk GCs. Moreover, we analyze this cluster’s behavior associated with the multiple-populations phenomenon. Methods. We obtained the stellar parameters and chemical abundances of light elements (Na, Al), iron-peak elements (V, Cr, Mn, Fe, Co, Ni, Cu), α-elements (O, Mg, Si, Ca, Ti) and heavy elements (Zr, Ba, Eu) in seven red giant members of NGC 6528 using high-resolution spectroscopy from FLAMES-UVES. Results. In six stars of our sample we obtained a mean iron content of [Fe/H] = − 0.14 ± 0.03 dex, in good agreement with other studies. We found no significant internal iron spread. We detected one candidate variable star, which was excluded from the mean in iron content, and derived a metallicity in this star of [Fe/H] = − 0.55 ± 0.04 dex. Moreover, we found no extended O-Na anticorrelation but instead only an intrinsic Na spread. In addition, NGC 6528 does not exhibit a Mg-Al anticorrelation, and no significant spread in either Mg or Al. The α and iron-peak elements show good agreement with the bulge field star trend. The heavy elements are slightly dominated by the r-process. The chemical analysis suggests an origin and evolution similar to that of typical old Galactic bulge field stars. Finally, we find remarkable agreement in the chemical patterns of NGC 6528 and another bulge GC, NGC 6553, suggesting a similar origin and evolution.

scholarly journals Kinematic and chemical analysis of PNe in NGC 3109

2016 ◽  
Vol 12 (S323) ◽  
pp. 390-391
Author(s):  
Sheila N. Flores-Dúran ◽  
Miriam Peña ◽  
María T. Ruiz
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Chemical Analysis ◽  
Stellar Evolution ◽  
Planetary Nebulae ◽  
High Resolution Spectroscopy ◽  
Irregular Galaxy ◽  
The One

AbstractWe present high resolution spectroscopy obtained with MIKE-Magellan and MES OAN-SPM of a number of planetary nebulae (PNe) and H ii regions, distributed along the dwarf irregular galaxy NGC 3109 and compare their kinematical behavior with the one of H i data. We aim to determine if there is a kinematical connection among these objects. We also perform a revision of the chemical composition of PNe and H ii regions in this galaxy and discuss it in comparison with stellar evolution models.

scholarly journals The Concept of Law and Models in Chemistry

2014 ◽  
Vol 22 (S1) ◽  
pp. S50-S86 ◽  
Author(s):  
Martin Quack
Keyword(s):  
High Resolution ◽  
Historical Development ◽  
High Resolution Spectroscopy ◽  
Molecular Models ◽  
Basic Concepts ◽  
The Concept Of Law ◽  
Atomic And Molecular Models ◽  
Concept Of Law

After a brief introduction to the basic concepts including some questions of language, the first part of this paper provides a brief survey of the historical development of laws and models in Chemistry, in particular atomic and molecular models. In the second part this paper deals with the fundamental role of the observation of symmetry violations in physics and chemistry in understanding the most ‘fundamental laws’ and current efforts towards such studies by means of high resolution spectroscopy of molecules. We conclude with a brief discussion of the implications for current unsolved problems in astrophysics and biology.

scholarly journals THE CHEMICAL COMPOSITION OF THE SURFACE LAYER OF ENAMEL DEPENDING ON ITS FUNCTIONAL STATE

2018 ◽  
pp. 66-71
Author(s):  
N. N. Pustovoitova ◽  
V. V. Kitel
Keyword(s):  
Surface Layer ◽  
Czech Republic ◽  
Great Britain ◽  
Chemical Composition ◽  
High Resolution ◽  
Dental Caries ◽  
Light Elements ◽  
Spectral Analyzer ◽  
Carious Lesions ◽  
Calcium Phosphorus

Objective: to study the chemical composition of the surface layer of enamel in dental caries depending on the activity of carious lesions. Material and methods. The chemical composition of the surface layer of enamel in teeth samples with arrested (n = 15) and active (n = 15) caries was studied using the high resolution SEM «Mira» by the firm «Tescan» (Czech Republic) with the micro spectral analyzer «INCA Energy 350» of the firm «Oxford Instruments Analytical» (Great Britain). Results. We have revealed reliable increases in carbon, oxygen and other light elements in the surface layer of the enamel at the area of active carious lesions in comparison with intact enamel and arrested carious lesions; significant decreases in the content of calcium, phosphorus, ratio of Ca / P coefficient for the surface layer of the enamel of active carious lesions in comparison with intact enamel and arrested carious lesions. We have revealed no reliable differences in the content of C, O, Ca, P, CI in the surface layer of intact enamel and that at the area of arrested no cavity caries.

scholarly journals A New Method for Measuring the Detailed Chemical Composition of Globular Clusters from High-Resolution, Integrated-Light Spectra

2002 ◽  
Vol 207 ◽  
pp. 739-742 ◽  
Author(s):  
Rebecca A. Bernstein ◽  
Andrew McWilliam
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Globular Clusters ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Analysis Method ◽  
Individual Stars ◽  
Light Spectra ◽  
History Of ◽  
Detailed Chemical

We are developing a method for measuring the detailed chemical composition and evolutionary history of extragalactic star clusters from high resolution spectra of their integrated light as one would from spectra of individual stars. In this paper, we show high signal-to-noise ratio echelle spectra of the integrated light of two Galactic globular clusters and equivalent-quality spectra of individual stars in those clusters in order to briefly illustrate some subtleties of the analysis method.

High-resolution spectroscopy of red giants and ‘yellow stragglers’ in the southern open cluster NGC 2539

2020 ◽  
Vol 494 (1) ◽  
pp. 1470-1489
Author(s):  
Cintia F Martinez ◽  
N Holanda ◽  
C B Pereira ◽  
N A Drake
Keyword(s):  
High Resolution ◽  
Open Cluster ◽  
Open Clusters ◽  
Solar Neighborhood ◽  
Spectroscopic Binaries ◽  
High Resolution Spectroscopy ◽  
Red Giants ◽  
Light Elements ◽  
Abundance Pattern ◽  
Solar Metallicity

ABSTRACT We present a detailed high-resolution spectroscopic analysis of 12 red giant stars, in single and binaries or multiples systems, classified as members of the intermediate-age (631 Myr) open cluster NGC 2539. We used FEROS echelle spectra and the standard LTE analysis to derive the atmospheric parameters for the stars and the abundance ratios of light elements (Li, C, N), light odd-Z elements (Na, Al), α-elements (Mg, Si, Ca, Ti), Fe-group elements (Cr, Fe, Ni), and n-capture elements (Y, Zr, Ce, Nd, Eu). Our results show that the sample star of NGC 2539 has low projected rotational velocities and an almost solar metallicity, with a mean of [Fe/H] = −0.03 ± 0.07 dex. The abundance pattern displays for the analyzed stars are, in general, similar to those presented by solar neighborhood stars, including giant members of others open clusters. In particular, light elements and Na abundance pattern shows anomalies resulting from the appearance of enriched material on the stellar surface, produced by mechanisms like the first dredge-up and/or thermohaline and rotation-induced mixing. We also identified two of the spectroscopic binaries of our sample as ‘yellow stragglers’ and we determined the nature of their companions.

Sign in / Sign up

Export Citation Format

Share Document