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J/ApJ/297/582 NGC 2213 BR photometry (Da Costa+, 1985)
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The age of the LMC globular cluster NGC 2213
Da Costa G.S., Mould J.R., Crawford M.D.
<Astrophys. J. 297, 582 (1985)>
=1985ApJ...297..582D (SIMBAD/NED BibCode)
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ADC_Keywords: Magellanic Clouds ; Clusters, globular ; Photometry, CCD
Keywords: clusters: globular - galaxies: Magellanic Cloud - stars: evolution
Abstract:
The age of the LMC red globular cluster NGC 2213 has been estimated as
1.3+/-0.5x10^9^yr from a color-magnitude diagram, derived from CCD
photometry, that reveals the cluster main sequence. The accuracy of
the age estimate, however, is limited by uncertainly in the LMC
distance modulus, by uncertainty in the cluster metal abundance which
appears to lie in the range one-half to one-sixth solar, by
uncertainty in the reddening of the cluster, and by uncertainty in the
extent to which the theoretical isochrones used for the age dating are
affected by the neglect, in standard stellar models, of the interior
mixing caused by convective overshoot in the stellar cores. Using the
adopted reddening of E(B-V)=0.09 and assuming Y=0.2, isochrone best
fits to the cluster main sequence are found for [M/H]=-0.3 if
(m-M)0=18.7 and for [M/H]=-0.7 if (m-M)0=18.2. After allowance for the
possible effects of convective overshoot, the corresponding ages are
0.9^+0.5^_-0.3_ and 1.6^+0.8_^-0.4_x10^9^yr. Plausible alterations in
the adopted reddening value and the adopted helium abundance also
yield ages within these limits.
Objects:
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RA (2000) DE Designation(s)
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06 10.7 -71 37 NGC 2213 = LW 419
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 24 342 NGC 2213 cluster photometry
table3 25 113 NGC 2213 field star photometry
table4 29 168 NGC 2213 photometry from short-exposure frames
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Byte-by-byte Description of file: table2 table3 table4
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Bytes Format Units Label Explanations
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1- 3 I3 --- Star Star number
5- 9 F5.2 mag Rmag R magnitude
11- 15 F5.2 mag B-R B- R color index
17- 19 I3 pix Xpos X position (1)
21- 23 I3 pix Ypos Y position (1)
25- 29 A5 --- Id Cross-Identification (only in table4) (2)
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Note (1): East is up, and south is to the left.
Note (2): Cross-identification to table1 and table2
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Table1: NGC 2213 secondary standards
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Star R B-R X Y
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1 17.54 2.39 34 313
2 17.83 1.59 34 430
3 18.45 1.41 56 197
4 16.68 1.41 56 197
5 18.56 1.46 104 119
6 17.62 1.56 153 478
7 17.62 1.56 153 478
8 17.99 1.69 159 444
9 17.33 1.77 189 382
10 17.81 1.67 213 454
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History: Prepared via OCR at CDS.
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(End) Marie-Jose Wagner, Patricia Bauer [CDS] 30-Sep-1996