scholarly journals Searching for multiple populations in Ruprecht 106

2021 ◽  
Author(s):  
H Frelijj ◽  
S Villanova ◽  
C Muñoz ◽  
J G Fernández-Trincado
Keyword(s):  
Globular Cluster ◽  
Stellar Population ◽  
Atmospheric Parameters ◽  
Photometric Analysis ◽  
Dynamical Study ◽  
Multiple Populations ◽  
Red Giant ◽  
Definition Of ◽  
Energy Plane ◽  
Giant Branch Stars

Abstract More than a decade has passed since the definition of Globular Cluster (GC) changed, and now we know that they host Multiple Populations (MPs). But few GCs do not share that behaviour and Ruprecht 106 is one of these clusters. We analyzed thirteen member red giant branch stars using spectra in the wavelength range 6120-6405 Å obtained through the GIRAFFE Spectrograph, mounted at UT2 telescope at Paranal, as well as the whole cluster using C, V, R and I photometry obtained through the Swope telescope at Las Campanas. Atmospheric parameters were determined from the photometry to determine Fe and Na abundances. A photometric analysis searching for MPs was also carried out. Both analyses confirm that Ruprecht 106 is indeed one on the few GCs to host Simple Stellar Population, in agreement with previous studies. Finally, a dynamical study concerning its orbits was carried out to analyse the possible extragalactic origin of the Cluster. The orbital integration indicates that this GC belongs to the inner halo, while an Energy plane shows that it cannot be accurately associated with any known extragalactic progenitor.

scholarly journals Chemical abundance analysis of red giant branch stars in the globular cluster E3

2018 ◽  
Vol 616 ◽  
pp. A181 ◽  
Author(s):  
L. Monaco ◽  
S. Villanova ◽  
G. Carraro ◽  
A. Mucciarelli ◽  
C. Moni Bidin
Keyword(s):  
Radial Velocity ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Abundance Ratio ◽  
Chemical Abundance ◽  
Chemical Abundances ◽  
Multiple Populations ◽  
Red Giant ◽  
A Minor ◽  
Giant Branch Stars

Context. Globular clusters are known to host multiple stellar populations, which are a signature of their formation process. The globular cluster E3 is one of the few low-mass globulars that is thought not to host multiple populations. Aims. We investigate red giant branch stars in E3 with the aim of providing a first detailed chemical inventory for this cluster, we determine its radial velocity, and we provide additional insights into the possible presence of multiple populations in this cluster. Methods. We obtained high-resolution FLAMES-UVES/VLT spectra of four red giant branch stars likely members of E3. We performed a local thermodynamic equilibrium abundance analysis based on one-dimensional plane parallel ATLAS9 model atmospheres. Abundances were derived from line equivalent widths or spectrum synthesis. Results. We measured abundances of Na and of iron peak (Fe, V, Cr, Ni, Mn), α(Mg, Si, Ca, Ti), and neutron capture elements (Y, Ba, Eu). The mean cluster heliocentric radial velocity, metallicity, and sodium abundance ratio are νhelio = 12.6 ± 0.4 km s−1(σ = 0.6 ± 0.2 km s−1), [Fe/H] = −0.89 ± 0.08 dex, and [Na/Fe] = 0.18 ± 0.07 dex, respectively. The low Na abundance with no appreciable spread is suggestive of a cluster dominated by first-generation stars in agreement with results based on lower resolution spectroscopy. The low number of stars observed does not allow us to rule out a minor population of second-generation stars. The observed chemical abundances are compatible with the trends observed in Milky Way stars.

scholarly journals Abundances of Na, Mg, and K in the atmospheres of red giant branch stars of Galactic globular cluster 47 Tucanae

2017 ◽  
Vol 604 ◽  
pp. A35 ◽  
Author(s):  
A. Černiauskas ◽  
A. Kučinskas ◽  
J. Klevas ◽  
D. Prakapavičius ◽  
S. Korotin ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Red Giant ◽  
Giant Branch Stars

scholarly journals Aluminium abundances in five discrete stellar populations of the globular cluster NGC 2808

2018 ◽  
Vol 615 ◽  
pp. A17 ◽  
Author(s):  
Eugenio Carretta ◽  
Angela Bragaglia ◽  
Sara Lucatello ◽  
Raffaele G. Gratton ◽  
Valentina D’Orazi ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Cluster Formation ◽  
Light Elements ◽  
Atmospheric Parameters ◽  
Proton Capture ◽  
Full Dataset ◽  
Self Consistent ◽  
Red Giant ◽  
Set Up ◽  
First Time

We observed a sample of 90 red giant branch (RGB) stars in NGC 2808 using FLAMES/GIRAFFE and the high resolution grating with the set-up HR21. These stars have previous accurate atmospheric parameters and abundances of light elements. We derived aluminium abundances for them from the strong doublet Al i 8772–8773 Å as in previous works of our group. In addition, we were able to estimate the relative CN abundances for 89 of the stars from the strength of a large number of CN features. When adding self-consistent abundances from previous UVES spectra analysed by our team, we gathered [Al/Fe] ratios for a total of 108 RGB stars in NGC 2808. The full dataset of proton-capture elements is used to explore in detail the five spectroscopically detected discrete components in this globular cluster. We found that various classes of polluters are required to reproduce (anti)-correlations among all proton-capture elements in the populations P2, I1, and I2 with intermediate composition. This is in agreement with the detection of lithium in lower RGB second generation stars, requiring at least two kind of polluters. For chemically homogeneous populations, the best subdivision of our sample is into six components as derived from statistical cluster analysis. By comparing different diagrams [element/Fe] versus [element/Fe], we show for the first time that a simple dilution model is not able to reproduce all the subpopulations in this cluster. Polluters of different masses are required. NGC 2808 is confirmed to be a tough challenge to any scenario for globular cluster formation.

scholarly journals The Stellar Populations of M32: Resolving the nearest elliptical with HST ACS/HRC

2009 ◽  
Vol 5 (S262) ◽  
pp. 135-138 ◽  
Author(s):  
Antonela Monachesi ◽  
S. C. Trager ◽  
Tod R. Lauer ◽  
Wendy Freedman ◽  
Alan Dressler ◽  
...  
Keyword(s):  
Stellar Population ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Horizontal Branch ◽  
Horizontal Branch Stars ◽  
Magnitude Diagram ◽  
Colour Distribution ◽  
Red Clump ◽  
Red Giant ◽  
Giant Branch Stars

AbstractWe present the deepest colour-magnitude diagram (CMD) of M32 to date, obtained from deep (F435W, F555W) photometry of HST ACS/HRC images. Due to the high resolution of our images, the small photometric errors, and the completeness level of our data we obtain the most detailed resolved photometric study of M32 to date. The CMD of M32 displays a wide colour distribution of red giant branch stars, mainly due to a metallicity spread, a strong red clump and bright asymptotic giant branch stars. The detection of a “blue plume” in M32 indicates the presence of a very young stellar population. There is not a noticeable presence of blue horizontal branch stars, suggesting that an old population with [Fe/H] < −1.5 does not significantly contribute to the light or mass of M32 in our observed fields.

scholarly journals Nucleosynthesis in the Stellar Systems ω Centauri and M22

2011 ◽  
Vol 28 (1) ◽  
pp. 28-37 ◽  
Author(s):  
G. S. Da Costa ◽  
A. F. Marino
Keyword(s):  
Globular Cluster ◽  
Total Mass ◽  
Large Range ◽  
Stellar System ◽  
Stellar Systems ◽  
Elemental Abundances ◽  
Two Systems ◽  
Red Giant ◽  
Using Data ◽  
Giant Branch Stars

AbstractThe stellar system ω Centauri (ω Cen) is well known for the large range in elemental abundances among its member stars. Recent work has indicated that the globular cluster M22 (NGC 6656) also possesses an internal abundance range, albeit substantially smallerthan that in ω Cen. Here we compare, as a function of [Fe/H], element-to-iron ratios in the two systems for a number of different elements using data from abundance analyses of red giant branch stars. It appears that the nucleosynthetic enrichment processes were very similar in these two systems despite the substantial difference in total mass.

scholarly journals Observing multiple populations in globular clusters with the ESO archive: NGC 6388 reloaded

2018 ◽  
Vol 614 ◽  
pp. A109 ◽  
Author(s):  
Eugenio Carretta ◽  
Angela Bragaglia
Keyword(s):  
Globular Clusters ◽  
First Generation ◽  
Spectroscopic Properties ◽  
Discrete Groups ◽  
Red Giants ◽  
Single Class ◽  
Multiple Populations ◽  
Telescope Facility ◽  
Red Giant ◽  
Giant Branch Stars

The metal-rich and old bulge globular cluster (GC) NGC 6388 is one of the most massive Galactic GCs (M ~ 106 M⊙). However, the spectroscopic properties of its multiple stellar populations rested only on 32 red giants (only 7 of which observed with UVES, the others with GIRAFFE), given the difficulties in observing a rather distant cluster, heavily contaminated by bulge and disc field stars. We bypassed the problem using the resources of the largest telescope facility ever: the European Southern Observatory (ESO) archive. By selecting member stars identified by other programmes, we derive atmospheric parameters and the full set of abundances for 15 species from high-resolution UVES spectra of another 17 red giant branch stars in NGC 6388. We confirm that no metallicity dispersion is detectable in this GC. About 30% of the stars show the primordial composition of first-generation stars, about 20% present an extremely modified second-generation composition, and 50% have an intermediate composition. The stars are clearly distributed in the Al–O and Na–O planes in three discrete groups. We find substantial hints that more than a single class of polluters is required to reproduce the composition of the intermediate component in NGC 6388. In the heavily polluted component the sum Mg+Al increases as Al increases. The sum Mg+Al+Si is constant, and is the fossil record of hot H-burning at temperatures higher than about 70 MK in the first-generation polluters that contributed to form multiple populations in this cluster.

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] &gt; -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.

scholarly journals STAR-TO-STAR IRON ABUNDANCE VARIATIONS IN RED GIANT BRANCH STARS IN THE GALACTIC GLOBULAR CLUSTER NGC 3201

2013 ◽  
Vol 764 (1) ◽  
pp. L7 ◽  
Author(s):  
Jennifer Simmerer ◽  
Inese I. Ivans ◽  
Dan Filler ◽  
Patrick Francois ◽  
Corinne Charbonnel ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Iron Abundance ◽  
Red Giant ◽  
Giant Branch Stars

scholarly journals The RR Lyrae Variables in M54 and the Sgr Dwarf Galaxy

2002 ◽  
Vol 207 ◽  
pp. 168-170
Author(s):  
C. Cacciari ◽  
M. Bellazzini ◽  
S. Colucci
Keyword(s):  
Recent Work ◽  
Globular Cluster ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Variable Stars ◽  
Ccd Photometry ◽  
Rr Lyrae ◽  
Red Giant

We report on new B, V and I CCD photometry of the globular cluster M54 that was aimed at the study of its variable stars. With respect to the previous most recent work on M54 we have nearly doubled the number of detected variable stars: M54 can now be classified as intermediate in the Oosterhoff groups. The metallicity can be estimated for the cluster and field red giant stellar population, and for the variables.

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