The relatively young, metal-poor and distant open cluster NGC 2324
We have obtained CCD photometry in the Johnson V, Kron-Cousins I and CT1 Washington systems for NGC 2324, a rich open cluster located ∼35° from the Galactic anticentre direction. We measured V magnitudes and V - I colours for 2865 stars and T1 magnitudes and C - T 1 colours for 1815 stars in an area...
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todo:paper_00046361_v418_n3_p979_Piatti2023-10-03T14:00:07Z The relatively young, metal-poor and distant open cluster NGC 2324 Piatti, A.E. Clariá, J.J. Ahumada, A.V. Galaxy: general Galaxy: open clusters and associations: individual: NGC 2324 Techniques: photometric Astrophysics Charge coupled devices Cosmic rays Galaxies Light absorption Photometry Galactic disc Isochrone fitting procedures Open clusters and association Astronomy We have obtained CCD photometry in the Johnson V, Kron-Cousins I and CT1 Washington systems for NGC 2324, a rich open cluster located ∼35° from the Galactic anticentre direction. We measured V magnitudes and V - I colours for 2865 stars and T1 magnitudes and C - T 1 colours for 1815 stars in an area of 13′.6 × 13′.6. The comparison of the cluster colour-magnitude diagrams with isochrones of the Geneva group yield E(V - 1) = 0.33 ± 0.07 and V - Mv = 13.70 ± 0.15 for log t = 8.65 (t = 440 Myr) and Z = 0.008 ([Fe/H] = -0.40), and E(C - T1) = 0.40 ± 0.10 and T 1 - MT1 = 13.65 ± 0.15 for the same age and metallicity level. The resulting E(V - I) reddening value implies E(B - V) = 0.25 ± 0.05 and a distance from the Sun of (3.8 ± 0.5) kpc. Star counts carried out within and outside the cluster region allowed us to estimate the cluster angular radius as 5′.3 ± 0′.3 (5.9 pc). When using the E(B - V) reddening value here derived and the original Washington photometric data of Geisler et al. (1991) for the stars confirmed as red cluster giants from Coravel radial velocities, we found [Fe/H] = -0.31 ± 0.04, which is in good agreement with the best fits of isochrones. Therefore, NGC 2324 is found to be a relatively young, metal-poor and distant open cluster located beyond the Perseus spiral arm. A comparison of NGC 2324 with 10 well-known open clusters of nearly the same age shows that the cluster metal abundance and its position in the Galaxy are consistent with the existence of a radial abundance gradient of -0.07 dex kpc-1 in the Galactic disc. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046361_v418_n3_p979_Piatti |
| institution |
Universidad de Buenos Aires |
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I-28 |
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R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
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Galaxy: general Galaxy: open clusters and associations: individual: NGC 2324 Techniques: photometric Astrophysics Charge coupled devices Cosmic rays Galaxies Light absorption Photometry Galactic disc Isochrone fitting procedures Open clusters and association Astronomy |
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Galaxy: general Galaxy: open clusters and associations: individual: NGC 2324 Techniques: photometric Astrophysics Charge coupled devices Cosmic rays Galaxies Light absorption Photometry Galactic disc Isochrone fitting procedures Open clusters and association Astronomy Piatti, A.E. Clariá, J.J. Ahumada, A.V. The relatively young, metal-poor and distant open cluster NGC 2324 |
| topic_facet |
Galaxy: general Galaxy: open clusters and associations: individual: NGC 2324 Techniques: photometric Astrophysics Charge coupled devices Cosmic rays Galaxies Light absorption Photometry Galactic disc Isochrone fitting procedures Open clusters and association Astronomy |
| description |
We have obtained CCD photometry in the Johnson V, Kron-Cousins I and CT1 Washington systems for NGC 2324, a rich open cluster located ∼35° from the Galactic anticentre direction. We measured V magnitudes and V - I colours for 2865 stars and T1 magnitudes and C - T 1 colours for 1815 stars in an area of 13′.6 × 13′.6. The comparison of the cluster colour-magnitude diagrams with isochrones of the Geneva group yield E(V - 1) = 0.33 ± 0.07 and V - Mv = 13.70 ± 0.15 for log t = 8.65 (t = 440 Myr) and Z = 0.008 ([Fe/H] = -0.40), and E(C - T1) = 0.40 ± 0.10 and T 1 - MT1 = 13.65 ± 0.15 for the same age and metallicity level. The resulting E(V - I) reddening value implies E(B - V) = 0.25 ± 0.05 and a distance from the Sun of (3.8 ± 0.5) kpc. Star counts carried out within and outside the cluster region allowed us to estimate the cluster angular radius as 5′.3 ± 0′.3 (5.9 pc). When using the E(B - V) reddening value here derived and the original Washington photometric data of Geisler et al. (1991) for the stars confirmed as red cluster giants from Coravel radial velocities, we found [Fe/H] = -0.31 ± 0.04, which is in good agreement with the best fits of isochrones. Therefore, NGC 2324 is found to be a relatively young, metal-poor and distant open cluster located beyond the Perseus spiral arm. A comparison of NGC 2324 with 10 well-known open clusters of nearly the same age shows that the cluster metal abundance and its position in the Galaxy are consistent with the existence of a radial abundance gradient of -0.07 dex kpc-1 in the Galactic disc. |
| format |
JOUR |
| author |
Piatti, A.E. Clariá, J.J. Ahumada, A.V. |
| author_facet |
Piatti, A.E. Clariá, J.J. Ahumada, A.V. |
| author_sort |
Piatti, A.E. |
| title |
The relatively young, metal-poor and distant open cluster NGC 2324 |
| title_short |
The relatively young, metal-poor and distant open cluster NGC 2324 |
| title_full |
The relatively young, metal-poor and distant open cluster NGC 2324 |
| title_fullStr |
The relatively young, metal-poor and distant open cluster NGC 2324 |
| title_full_unstemmed |
The relatively young, metal-poor and distant open cluster NGC 2324 |
| title_sort |
relatively young, metal-poor and distant open cluster ngc 2324 |
| url |
http://hdl.handle.net/20.500.12110/paper_00046361_v418_n3_p979_Piatti |
| work_keys_str_mv |
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