The chemical compositions and evolutionary status of red giants in
                    the open cluster NGC 752

Topcu, Gamze Bõcek; Afşar, Melike; Schaeuble, Marc; Sneden, Christopher

doi:10.1093/mnras/stu2380

Cited by 28 publications

(26 citation statements)

References 83 publications

(92 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For Cr ii we have only five transitions (4588.20, 4592.05, 5237.32, 5305.87 and 5334.86). Our adopted transition probabilities from Böcek Topcu et al (2015) have recently been revised by Lawler et al (2017). For our lines the scatter old-new in log gf values is high but the mean is essentially the same.…”

Section: Abundance Ratiosmentioning

confidence: 97%

A Spectroscopic Survey of Field Red Horizontal-branch Stars

Afşar

Bozkurt

Topcu

et al. 2018

View full text Add to dashboard Cite

A metallicity, chemical composition, and kinematic survey has been conducted for a sample of 340 candidate field red horizontal branch stars. High resolution, high signal-to-noise spectra were gathered with the McDonald Observatory 2.7m Tull and the Hobby-Eberly Telescope echelle spectrographs, and were used to determine effective temperatures, surface gravities, microturbulent velocities, [Fe/H] metallicities, and abundance ratios [X/Fe] for seven α and Fe-group species. The derived temperatures and gravities confirm that at least half of the candidates are true RHB stars, with (average) parameters T eff ∼ 5000 K, log g ∼ 2.5. From the α abundances alone the thin and thick Galactic populations are apparent in our sample. Space motions for 90% of the program stars were computed from Hipparcos and Gaia parallaxes and proper motions. Correlations between chemical compositions and Galactic kinematics clearly indicate the existence of both thin and thick disk RHB stars.

show abstract

Section: Abundance Ratiosmentioning

confidence: 97%

A Spectroscopic Survey of Field Red Horizontal-branch Stars

Afşar

Bozkurt

Topcu

et al. 2018

View full text Add to dashboard Cite

show abstract

“…In the present paper we therefore list the correct values for the higher and lower quality data. Since publication of Paper II, some new studies were made (Boesgaard et al 2013;Böcek Topcu et al 2015;Carraro et al 2014b;Donati et al 2015;Magrini et al 2014Magrini et al , 2015Molenda-Żakowicz et al 2014;Monaco et al 2014;Reddy et al 2015), which we examined the same way as described in Paper II. This adds ten open clusters to our list (Berkeley 81, NGC 1342, NGC 1662, NGC 1912, NGC 2354 and supplementary data for NGC 752, NGC 2447, NGC 2632, and NGC 6705.…”

Section: Spectroscopic Metallicitiesmentioning

confidence: 99%

On the metallicity of open clusters

Netopil

Paunzen

Heiter

et al. 2016

A&A

205

243

View full text Add to dashboard Cite

Context. Open clusters are known as excellent tools for various topics in Galactic research. For example, they allow accurately tracing the chemical structure of the Galactic disc. However, the metallicity is known only for a rather low percentage of the open cluster population, and these values are based on a variety of methods and data. Therefore, a large and homogeneous sample is highly desirable. Aims. In the third part of our series we compile a large sample of homogenised open cluster metallicities using a wide variety of different sources. These data and a sample of Cepheids are used to investigate the radial metallicity gradient, age effects, and to test current models. Methods. We used photometric and spectroscopic data to derive cluster metallicities. The different sources were checked and tested for possible offsets and correlations. Results. In total, metallicities for 172 open cluster were derived. We used the spectroscopic data of 100 objects for a study of the radial metallicity distribution and the age-metallicity relation. We found a possible increase of metallicity with age, which, if confirmed, would provide observational evidence for radial migration. Although a statistical significance is given, more studies are certainly needed to exclude selection effects, for example. The comparison of open clusters and Cepheids with recent Galactic models agrees well in general. However, the models do not reproduce the flat gradient of the open clusters in the outer disc. Thus, the effect of radial migration is either underestimated in the models, or an additional mechanism is at work. Conclusions. Apart from the Cepheids, open clusters are the best tracers for metallicity over large Galactocentric distances in the Milky Way. For a sound statistical analysis, a sufficiently large and homogeneous sample of cluster metallicities is needed. Our compilation is currently by far the largest and provides the basis for several basic studies such as the statistical treatment of the Galactic cluster population, or evolutionary studies of individual star groups in open clusters.

show abstract

“…Surface abundances of C and N are expected to be altered in giants that have gone through the first dredge-up; [C/Fe] ∼ −0.20 dex and [N/Fe] ∼ +0.40 dex (see, e.g. Tautvaišienė et al 2015Tautvaišienė et al , 2016Drazdauskas et al 2016a,b;Böcek Topcu et al 2015Szigeti et al 2018, for some recent references). The C and N abundances seem consistent with the stars having experienced first dredge-up, although N in the star CNAME 18181062-3246291 seems to have been only mildly affected.…”

Section: Chemical Abundancesmentioning

confidence: 99%

TheGaia-ESO Survey: properties of newly discovered Li-rich giants

Smiljanić

Franciosini

Bragaglia³

et al. 2018

A&A

View full text Add to dashboard Cite

Aims. We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including the first Li-rich giant with an evolutionary stage confirmed by CoRoT (Convection, Rotation and planetary Transits) data. We present a detailed overview of the properties of these 20 stars. Methods. Atmospheric parameters and abundances were derived in model atmosphere analyses using medium-resolution GIRAFFE or high-resolution UVES (Ultraviolet and Visual Echelle Spectrograph) spectra. These results are part of the fifth internal data release of the Gaia-ESO Survey. The Li abundances were corrected for non-local thermodynamical equilibrium effects. Other stellar properties were investigated for additional peculiarities (the core of strong lines for signs of magnetic activity, infrared magnitudes, rotational velocities, chemical abundances, and Galactic velocities). We used Gaia DR2 parallaxes to estimate distances and luminosities.Results. The giants have A(Li) > 2.2 dex. The majority of them (14 of 20 stars) are in the CoRoT fields. Four giants are located in the field of three open clusters, but are not members. Two giants were observed in fields towards the Galactic bulge, but likely lie in the inner disc. One of the bulge field giants is super Li-rich with A(Li) = 4.0 dex. Conclusions. We identified one giant with infrared excess at 22µm. Two other giants, with large v sin i, might be Li-rich because of planet engulfment. Another giant is found to be barium enhanced and thus could have accreted material from a former asymptotic giant branch companion. Otherwise, in addition to the Li enrichment, the evolutionary stages are the only other connection between these new Li-rich giants. The CoRoT data confirm that one Li-rich giant is at the core-He burning stage. The other giants are concentrated in close proximity to the red giant branch luminosity bump, the core-He burning stages, or the early-asymptotic giant branch. This is very clear from the Gaia-based luminosities of the Li-rich giants. This is also seen when the CoRoT Li-rich giants are compared to a larger sample of 2252 giants observed in the CoRoT fields by the Gaia-ESO Survey, which are distributed throughout the red giant branch in the T eff -log g diagram. These observations show that the evolutionary stage is a major factor for the Li enrichment in giants. Other processes, such as planet accretion, contribute at a smaller scale.

show abstract

The chemical compositions and evolutionary status of red giants in the open cluster NGC 752

Cited by 28 publications

References 83 publications

A Spectroscopic Survey of Field Red Horizontal-branch Stars

A Spectroscopic Survey of Field Red Horizontal-branch Stars

On the metallicity of open clusters

TheGaia-ESO Survey: properties of newly discovered Li-rich giants

Contact Info

Product

Resources

About