Variable stars in the field of the old open cluster NGC 2243

Kałużny, J.; Krzemiński, W.; Mazur, B.

doi:10.1051/aas:1996199

Cited by 38 publications

(75 citation statements)

References 14 publications

(19 reference statements)

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“…Instead the effect on the [Ca/Fe] ratio is negligible. Our temperature scale is consistent with that of Kaluzny et al (1996); this is not surprising given the adoption of the same photometry and reddening. Figure 6 shows the position of the stars on a T eff − V space, similar to a color magnitude diagram.…”

Section: Error Estimatessupporting

confidence: 77%

“…Gratton & Contarini (1994) confirmed this low metallicity using high-resolution spectra. They determined the iron abundance in two giants of the cluster and found Kaluzny et al (1996) found E(V − I) = 0.10 ± 0.04. Kaluzny et al (2006) extended their study of NGC 2243 to the analysis of detached eclipsing binaries.…”

Section: Ngc 2243: An Old Metal-poor Open Clustermentioning

confidence: 99%

“…The final values of the difference in the computed RV is given in Fig. 2, as well as the distribution, Kaluzny et al (1996), while squares, triangles, and diamonds mark the positions of red giants, variables, and blue stragglers taken from the literature (WEBDA database). Circles refer to our targets, where the position of the most-probable single stars and binaries or non-members (from our radial velocity analysis) are marked in green and blue, respectively, while red giants from the literature (WEBDA database) are in red.…”

Section: Radial Velocitiesmentioning

confidence: 99%

“…The chosen reddening from Kaluzny et al (1996) is on the high side of the different estimations and our effective temperatures are in fact higher by about 200 K compared to the low temperature scale adopted, for instance by Hill & Pasquini (2000). A difference of this magnitude would shift our abundances by accounting for a lower Li of about 0.15 dex and a lower [Fe/H] of 0.15 dex and a change in the ionization balance Fe i -Fe ii by 0.12 dex.…”

Section: Error Estimatesmentioning

confidence: 99%

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Lithium abundance in the metal-poor open cluster NGC 2243

François¹,

Pasquini²,

Biazzo³

et al. 2013

A&A

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Context. Lithium is a fundamental element for studying the mixing mechanisms acting in the stellar interiors, for understanding the chemical evolution of the Galaxy and the Big Bang nucleosynthesis. The study of Li in stars of open clusters (OC) allows a detailed comparison with stellar evolutionary models and permits us to trace its galactic evolution. The OC NGC 2243 is particularly interesting because of its low metallicity ([Fe/H] = −0.54 ± 0.10 dex). Aims. We measure the iron and lithium abundance in stars of the metal-poor OC NGC 2243. The first aim is to determine whether the Li dip extends to such low metallicities, the second is to compare the results of our Li analysis in this OC with those present in 47 Tuc, a globular cluster of similar metallicity. Methods. We performed a detailed analysis of high-resolution spectra obtained with the multi-object facility FLAMES at the ESO VLT 8.2 m telescope. Lithium abundance was derived through line equivalent widths and the OSMARCS atmosphere models. Iron abundances from Fe i and Fe ii lines have also been measured and used to check the atmospheric model parameters.Results. The Li line is detected in 27 stars confirmed as likely cluster members by repeated radial velocity measurements. We determine a Li dip center of 1.06 M , which is much smaller than that observed in solar metallicity and metal-rich clusters. This finding confirms and strengthens the conclusion that the mass of the stars in the Li dip strongly depends on stellar metallicity. The mean Li abundance of the cluster is log n(Li) = 2.70 dex, which is substantially higher than that observed in 47 Tuc. We estimated an iron abundance of [Fe/H] = −0.54 ± 0.10 dex for NGC 2243, which is similar (within the errors) to previous findings. The [α/Fe] content ranges from 0.00 ± 0.14 for Ca to 0.20 ± 0.22 for Ti, which is low when compared to thick disk stars and to Pop II stars, but compatible with thin disk objects. We found a mean radial velocity of 61.9 ± 0.8 km s −1 for the cluster. Conclusions. We confirm a correlation between the Li dip cool-side position in mass as a function of the cluster's [Fe/H]. The Li abundance found in the metal-poor OC NGC 2243 agrees well with results obtained for the interstellar medium in the Small Magellanic Cloud having similar low metallicity. This value of Li is comparable to the primordial Li abundance deduced from WMAP measurements, therefore putting strong constraints on the models of Li enrichment during the early history of our Galaxy.

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Section: Error Estimatessupporting

confidence: 77%

Section: Ngc 2243: An Old Metal-poor Open Clustermentioning

confidence: 99%

Section: Radial Velocitiesmentioning

confidence: 99%

Section: Error Estimatesmentioning

confidence: 99%

See 2 more Smart Citations

Lithium abundance in the metal-poor open cluster NGC 2243

François¹,

Pasquini²,

Biazzo³

et al. 2013

A&A

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“…There are some indications that the Friel et al (2002) [ Fe/ H ] References.-Galactic coordinates, reddenings, and distances for globular clusters are from Harris (1996); Galactic coordinates, reddenings, and distances for open clusters are from Friel et al (2002). Sources for photometry: (1) Kaluzny et al 1998; (2) Piotto et al 2002;(3) Feltzing & Gilmore 2000;(4) Chaboyer et al 2000;(5) this paper; (6) Kaluzny 1988; (7) Carraro et al 2001;(8) Kassis et al 1997;(9) Bergbusch et al 1991;(10) Anthony-Twarog et al 1990;(11) Kim et al 2001;(12) Sandquist 2004;(13) Stetson et al 2003;(14) Kalirai et al 2001;(15) Andreuzzi et al 2004;(16) Durgapal et al 2001;(17) Tosi et al 1998;(18) Guetter 1993;(19) Kaluzny & Mazur 1991;(20) Gozzoli et al 1996. All OC photometry was obtained from WEBDA, maintained by J.-C. Mermilliod ( http:// obswww.unige.ch /webda /navigation.html).…”

Section: Discussionmentioning

confidence: 98%

UBVICCD Photometry of the Old Open Cluster Berkeley 17

Krusberg¹,

Chaboyer²

2006

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Photometric UBVI CCD photometry is presented for NGC 188 and Berkeley 17. Color-magnitude diagrams (CMDs) are constructed and reach well past the main-sequence turnoff for both clusters. Cluster ages are determined by means of isochrone fitting to the cluster CMDs. These fits are constrained to agree with spectroscopic metallicity and reddening estimates. Cluster ages are determined to be 7:0 AE 0:5 Gyr for NGC 188 and 10:0 AE 1:0 Gyr for Berkeley 17, where the errors refer to uncertainties in the relative age determinations. These ages are compared to the ages of relatively metal-rich inner halo/thick-disk globular clusters and other old open clusters. Berkeley 17 and NGC 6791 are the oldest open clusters, with ages of 10 Gyr. They are 2 Gyr younger than the thick-disk globular clusters. These results confirm the status of Berkeley 17 as one of the oldest known open clusters in the Milky Way, and its age provides a lower limit to the age of the Galactic disk.

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The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with HST

Zoccali¹,

Renzini²,

Ortolani³

et al. 2002

New Quests in Stellar Astrophysics: The Link Between Stars and Cosmology

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WFPC2 images obtained with the Hubble Space telescope 4.16 years apart have allowed us to measure the proper motion of the metal rich globular cluster NGC 6553 with respect to the background bulge stars. With a space velocity of (Π, Θ, W ) = (-3.5, 230, -3) km s −1 , NGC 6553 follows the mean rotation of both disk and bulge stars at a Galactocentric distance of 2.7 kpc. While the kinematics of the cluster is consistent with either a bulge or a disk membership, the virtual identity of its stellar population with that of the bulge cluster NGC 6528 makes its bulge membership more likely. The astrometric accuracy is high enough for providing a measure of the bulge proper motion dispersion and confirming its rotation. A selection of stars based on the proper motions produced an extremely well defined cluster color-magnitude diagram (CMD), essencially free of bulge stars. The improved turnoff definition in the decontaminated CMD confirms an old age for the cluster (∼ 13 Gyr) indicating that the bulge underwent a rapid chemical enrichment while being built up at in the early Universe. An additional interesting feature of the cluster color-magnitude diagram is a significant number of blue stragglers stars, whose membership in the cluster is firmly established from their proper motions.

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Variable stars in the field of the old open cluster NGC 2243

Cited by 38 publications

References 14 publications

Lithium abundance in the metal-poor open cluster NGC 2243

Lithium abundance in the metal-poor open cluster NGC 2243

UBVICCD Photometry of the Old Open Cluster Berkeley 17

The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with HST

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