scholarly journals Chemical Abundances in Giant Stars of the Tidally Disrupted Globular Cluster NGC 6712 from High‐Resolution Infrared Spectroscopy

2008 ◽  
Vol 689 (2) ◽  
pp. 1020-1030 ◽  
Author(s):  
David Yong ◽  
Jorge Meléndez ◽  
Katia Cunha ◽  
Amanda I. Karakas ◽  
John E. Norris ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
High Resolution ◽  
Globular Cluster ◽  
Chemical Abundances ◽  
Giant Stars

scholarly journals Chemical Abundances in 12 Red Giants of the Large Magellanic Cloud from High-Resolution Infrared Spectroscopy

2002 ◽  
Vol 124 (6) ◽  
pp. 3241-3254 ◽  
Author(s):  
Verne V. Smith ◽  
Kenneth H. Hinkle ◽  
Katia Cunha ◽  
Bertrand Plez ◽  
David L. Lambert ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
High Resolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Red Giants ◽  
Chemical Abundances

scholarly journals Galactic or extragalactic chemical tagging for NGC 3201?

2018 ◽  
Vol 614 ◽  
pp. A146 ◽  
Author(s):  
B. Dias ◽  
I. Araya ◽  
J. P. Nogueira-Cavalcante ◽  
L. Saker ◽  
A. Shokry
Keyword(s):  
High Resolution ◽  
Globular Cluster ◽  
High Resolution Spectroscopy ◽  
Low Resolution ◽  
Element Abundances ◽  
Giant Stars ◽  
Mass Size ◽  
Red Giant ◽  
Process Element ◽  
Size Relation

Context. The origin of the globular cluster (GC) NGC 3201 is under debate. Its retrograde orbit points to an extragalactic origin, but no further chemical evidence supports this idea. Light-element chemical abundances are useful to tag GCs and can be used to shed light on this discussion. Aims. Recently it was shown that the CN and CH indices are useful to identify GCs that are anomalous to those typically found in the Milky Way. A possible origin of anomalous clusters is the merger of two GCs and/or the nucleus of a dwarf galaxy. We aim to derive CN and CH band strengths for red giant stars in NGC3201 and compare these with photometric indices and high-resolution spectroscopy and discuss in the context of GC chemical tagging. Methods. We measure molecular band indices of S(3839) and G4300 for CN and CH, respectively from low-resolution spectra of red giant stars. Gravity and temperature effects are removed. Photometric indices are used to indicate further chemical information on C+N+O or s-process element abundances that are not derived from low-resolution spectra. Results. We found three groups in the CN–CH distribution. A main sequence (S1), a secondary less-populated sequence (S2), and a group of peculiar (pec) CN-weak and CH-weak stars, one of which was previously known. The three groups seem to have different C+N+O and/or s-process element abundances, to be confirmed by high-resolution spectroscopy. These are typical characteristics of anomalous GCs. The CN distribution of NGC 3201 is quadrimodal, which is more common in anomalous clusters. However, NGC 3201 does not belong to the trend of anomalous GCs in the mass-size relation. Conclusions. The globular cluster NGC 3201 shows signs that it can be chemically tagged as anomalous: it has an unusual CN–CH relation, indications that pec-S1-S2 is an increasing sequence of C+N+O or s-process element abundances, and a multi-modal CN distribution that seems to correlate with s-process element abundances. The non-anomalous characteristics are that it has a debatable Fe-spread and it does not follow the trend of mass size of all anomalous clusters. Three scenarios are postulated here: (i) if the sequence pec-S1-S2 has increasing C+N+O and s-process element abundances, NGC 3201 would be the first anomalous GC outside of the mass-size relation; (ii) if the abundances are almost constant, NGC 3201 would be the first non-anomalous GC with multiple CN–CH anti-correlation groups; or (iii) it would be the first anomalous GC without variations in C+N+O and s-process element abundances. In all cases, the definition of anomalous clusters and the scenario in which they have an extragalactic origin must be revised.

scholarly journals A high-resolution spectroscopic study of two new Na- and Al-rich field giants–likely globular cluster escapees in the Galactic halo

2020 ◽  
Vol 494 (1) ◽  
pp. 36-43
Author(s):  
Avrajit Bandyopadhyay ◽  
Sivarani Thirupathi ◽  
Timothy C Beers ◽  
A Susmitha
Keyword(s):  
High Resolution ◽  
Spectroscopic Study ◽  
Globular Cluster ◽  
Galactic Halo ◽  
Light Element ◽  
Echelle Spectrograph ◽  
Chemical Enrichment ◽  
Giant Stars ◽  
Shed Light

ABSTRACT The stars SDSS J0646+4116 and SDSS J1937+5024 are relatively bright stars that were initially observed as a part of the SDSS/MARVELS pre-survey. They were selected, on the basis of their weak CH G bands, along with a total of 60 others, in the range of halo globular cluster (GC) metallicities for high-resolution spectroscopic follow-up as a part of the HESP-GOMPA survey (Hanle Echelle SPectrograph – Galactic survey Of Metal Poor stArs). The stars exhibit typical nucleosynthesis signatures expected from the so-called second-generation stars of GCs. The light-element anticorrelation of Mg–Al is detected, along with elevated abundances of Na. Carbon is found to be depleted, which is compatible with expectation. Lithium is also detected in SDSS J0646+4116 and SDSS J1937+5024; the measured abundances are similar to those of normal halo giant stars. These bright escapees provide a unique opportunity to study the nucleosynthesis events of GC in great detail, and shed light on their chemical-enrichment histories.

Element abundances from B stars in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 388-389 ◽  
Author(s):  
A. Jüttner ◽  
O. Stahl ◽  
B. Wolf ◽  
B. Baschek
Keyword(s):  
High Resolution ◽  
Globular Cluster ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Comparison Star ◽  
Chemical Abundances ◽  
B Stars ◽  
Element Abundances

High resolution spectrograms of B stars in the blue globular cluster NGC 2004, located in the Large Magellanic Cloud (LMC), have been used to derive chemical abundances, differentially with respect to a galactic comparison star.

scholarly journals Chemical Abundances of Red Giant Stars in the Globular Cluster M107 (NGC 6171)

2011 ◽  
Vol 123 (908) ◽  
pp. 1139-1148 ◽  
Author(s):  
Julia E. O’Connell ◽  
Christian I. Johnson ◽  
Catherine A. Pilachowski ◽  
Geoffrey Burks
Keyword(s):  
Globular Cluster ◽  
Chemical Abundances ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

scholarly journals High-resolution spectroscopy of giant stars in the open clusters IC 4651 and IC 4725

2017 ◽  
Vol 95 (9) ◽  
pp. 862-868 ◽  
Author(s):  
Orlando J. Katime Santrich ◽  
Silvia Rossi
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Open Clusters ◽  
High Resolution Spectroscopy ◽  
Local Thermal Equilibrium ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Abundance Pattern ◽  
Giant Stars ◽  
Disk Structure

Open clusters are important astrophysical laboratories to study the stellar formation and evolution and to verify the disk structure of the Milky Way. We present calculations of stellar atmospheric parameters and s-process abundances for nine giant stars in the galactic open clusters IC 4651 and IC 4725. These objects have their memberships confirmed from dynamic studies and chemical analysis. The high-resolution spectra are available in the FEROS ESO archive. We have applied a line by line analysis relative to Juno solar spectrum to determine the stellar atmospheric parameters and chemical abundances of Y II, Zr I, La II, Ce II, and Nd II under the local thermal equilibrium hypothesis. The obtained results were compared to the literature values. The derived s-process abundance pattern agrees with the most recent behaviors reported for giant stars in galactic open clusters.

scholarly journals Chemical Abundances of Luminous Cool Stars in the Galactic Center from High‐Resolution Infrared Spectroscopy

2007 ◽  
Vol 669 (2) ◽  
pp. 1011-1023 ◽  
Author(s):  
Katia Cunha ◽  
Kris Sellgren ◽  
Verne V. Smith ◽  
Solange V. Ramirez ◽  
Robert D. Blum ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
High Resolution ◽  
Galactic Center ◽  
Chemical Abundances ◽  
Cool Stars

scholarly journals Chemodynamics of newly identified giants with a globular cluster like abundance patterns in the bulge, disc, and halo of the Milky Way

2019 ◽  
Vol 488 (2) ◽  
pp. 2864-2880 ◽  
Author(s):  
José G Fernández-Trincado ◽  
Timothy C Beers ◽  
Baitian Tang ◽  
Edmundo Moreno ◽  
Angeles Pérez-Villegas ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
First Generation ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Main Element ◽  
Chemical Abundances ◽  
Giant Stars ◽  
Halo Population ◽  
Process Elements

ABSTRACT The latest edition of the APOGEE-2/DR14 survey catalogue and the first Payne data release of APOGEE abundance determinations by Ting et al. are examined. We identify 31 previously unremarked metal-poor giant stars with anomalously high levels of [N/Fe] abundances, which is not usually observed among metal-poor stars in the Milky Way. We made use of the Brussels Automatic Stellar Parameter (BACCHUS) code to re-derive manually the chemical abundances of 31 field stars in order to compile the main element families, namely the light elements (C, N), a-elements (O, Mg, Si), iron-peak element (Fe), s-process elements (Ce, Nd), and the light odd-Z element (Na, Al). We have found all these objects have a [N/Fe] ≳ +0.5, and are thus identified here as nitrogen-rich stars. An orbital analysis of these objects revealed that a handful of them shares the orbital properties of the bar/bulge, and possibly linked to tidal debris of surviving globular clusters trapped into the bar component. Three of the 31 stars are actually halo interlopers into the bulge area, which suggests that halo contamination is not insignificant when studying N-rich stars found in the inner Galaxy, whereas the rest of the N-rich stars share orbital properties with the halo population. Most of the newly identified population exhibits chemistry similar to the so-called second-generation globular cluster stars (enriched in aluminum, [Al/Fe] ≳ +0.5), whereas a handful of them exhibit lower abundances of aluminum, [Al/Fe] < +0.5, which are thought to be chemically associated with the first generation of stars, as seen in globular clusters, or compatible with origin from a tidally disrupted dwarf galaxy.

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