Possibility of mass loss in the red-giant stage from H-R diagrams of galactic clusters

Barbaro, G.; Dallaporta, N.; Fabris, G.

doi:10.1007/bf00649599

Cited by 27 publications

(10 citation statements)

References 11 publications

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“…So that we have adopted an age for NGC 2323 of 100 Myr. This value is intermediate between those obtained by Barbaro et al (1969) and Mostafa et al (1983).…”

Section: Cluster Agecontrasting

confidence: 72%

“…This cluster was studied by several authors using photographic photometry (see, e.g., Cuffey 1941;Hoag et al 1961;Mostafa et al 1983), who placed it between 520 pc (Rieke 1935) and 1170 pc (Hoag et al 1961) from the sun. Although the age of NGC 2323 was determined by Barbaro et al (1969) and Mostafa et al (1983), there is no agreement between both estimations. In fact, the former derived an age of (6 ± 1) 10 7 yr, whereas the latter obtained 1.4 10 8 yr.…”

Section: Introductionmentioning

confidence: 95%

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Photometric study of the open cluster NGC 2323

Clariá

Piatti

Lapasset

1998

Astron. Astrophys. Suppl. Ser.

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Abstract. UBV photoelectric photometry for 175 stars in the field of the southern open cluster NGC 2323, supplemented by DDO photometry of 5 probable giants, is presented. The analysis of the photometric data yields 109 probable members; one of them being a red giant, and 3 possible members. The reddening across the cluster is slightly variable and the mean value E(B − V ) = 0.25. The apparent cluster distance modulus is 10.62, corresponding to a distance of 940 pc. The age, determined by fitting isochrones with core overshooting, turns out to be 100 ± 20 Myr. Other fundamental cluster parameters are also determined. NGC 2323 appears not to be physically connected to the CMa OB1 association.

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“…So that we have adopted an age for NGC 2323 of 100 Myr. This value is intermediate between those obtained by Barbaro et al (1969) and Mostafa et al (1983).…”

Section: Cluster Agecontrasting

confidence: 72%

Section: Introductionmentioning

confidence: 95%

Photometric study of the open cluster NGC 2323

Clariá

Piatti

Lapasset

1998

Astron. Astrophys. Suppl. Ser.

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“…Here we consider the distribution based on the data of Becker & Fenkart (1971). The ages were based on the age calibration of Barbaro et al (1969) and data on the colours and spectral classes of the brightest and bluest main sequence stars of the clusters. The clusters containing stars with spectral classes earlier than B2 were excluded from consideration.…”

Section: Comparison With the Literaturementioning

confidence: 99%

Global survey of star clusters in the Milky Way

Пискунов

Just

Kharchenko

et al. 2018

A&A

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Context. The all-sky Milky Way Star Clusters (MWSC) survey provides uniform and precise ages, along with other relevant parameters, for a wide variety of clusters in the extended solar neighbourhood. Aims. In this study we aim to construct the cluster age distribution, investigate its spatial variations, and discuss constraints on cluster formation scenarios of the Galactic disk during the last 5 Gyrs. Methods. Due to the spatial extent of the MWSC, we have considered spatial variations of the age distribution along galactocentric radius RG, and along Z-axis. For the analysis of the age distribution we used 2242 clusters, which all lie within roughly 2.5 kpc of the Sun. To connect the observed age distribution to the cluster formation history we built an analytical model based on simple assumptions on the cluster initial mass function and on the cluster mass-lifetime relation, fit it to the observations, and determined the parameters of the cluster formation law. Results. Comparison with the literature shows that earlier results strongly underestimated the number of evolved clusters with ages t ≳ 100 Myr. Recent studies based on all-sky catalogues agree better with our data, but still lack the oldest clusters with ages t ≳ 1 Gyr. We do not observe a strong variation in the age distribution along RG, though we find an enhanced fraction of older clusters (t > 1 Gyr) in the inner disk. In contrast, the distribution strongly varies along Z. The high altitude distribution practically does not contain clusters with t < 1 Gyr. With simple assumptions on the cluster formation history, the cluster initial mass function and the cluster lifetime we can reproduce the observations. The cluster formation rate and the cluster lifetime are strongly degenerate, which does not allow us to disentangle different formation scenarios. In all cases the cluster formation rate is strongly declining with time, and the cluster initial mass function is very shallow at the high mass end.

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“…However, for the OCs, NGC 6694, NGC 7062, NGC 1857, Haf 08, NGC 2186, NGC 6802, and NGC 436, these differences are sometimes larger, at the level of ∆(V 0 -M V ) = [−1.17, + 1.10], greater than we would like due to various systematic problems in the analyses. For instance, although the reddenings are nearly identical for NGC 1857, the theoretical solar-abundance ZAMS of Barbaro et al (1969) has been used by Babu (1989) for deriving their distance modulus, whereas the M08 isochrone with Z = +0.008 has been utilised in our work. For Be 73, the heavy-element abundances of the literature and of this work are almost identical, but for this cluster our E(B-V ) = 0.28 does not agree well with the E(B-V ) = 0.11 of Carraro et al (2007).…”

Section: Correlations Of the Interstellar Reddeningsmentioning

confidence: 99%

CCD UBV(RI)C photometry of twenty open clusters

Oralhan¹,

Karataş²,

Schuster³

et al. 2015

New Astronomy

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Fundamental astrophysical parameters have been derived for 20 open clusters (OCs) using CCD UBV(RI) C photometric data observed with the 84 cm telescope at the San Pedro Mártir National Astronomical Observatory, México.The interstellar reddenings, metallicities, distances, and ages have been compared to the literature values. Significant differences are usually due to the usage of diverse empirical calibrations and differing assumptions, such as concerning cluster metallicity, as well as distinct isochrones which correspond to differing element-abundance ratios, internal stellar physics, and photometric systems. Different interstellar reddenings, as well as varying reduction and cluster-membership techniques, are also responsible for these kinds of systematic differences and errors.The morphological ages, which are derived from the morphological indices (δV and δ1) in the CM diagrams, are in good agreement with the isochrone ages of 12 OCs, those with good red clump (RC) and red giant (RG) star candidates. No metal abundance gradient is detected for the range 6.82 ≤ R GC ≤ 15.37 kpc, nor any correlation between the cluster ages and metal abundances for these 20 OCs.Young, metal-poor OCs, observed here in the third Galactic quadrant, may be associated with stellar over-densities, such as that in Canis Major (Martin et al.) and the Monoceros Ring (Newberg et al.), or signatures of past accretion events, as discussed by Yong et al. and Carraro et al.

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Possibility of mass loss in the red-giant stage from H-R diagrams of galactic clusters

Cited by 27 publications

References 11 publications

Photometric study of the open cluster NGC 2323

Photometric study of the open cluster NGC 2323

Global survey of star clusters in the Milky Way

CCD UBV(RI)C photometry of twenty open clusters

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