J/PASP/106/486 Mel 66 CCD photometry (Anthony-Twarog+, 1994)
vbyHbeta CCD photometry of Melotte 66: a disk analog of Omega Centauri?
Anthony-Twarog B.J., Twarog B.A., Sheeran M.
<Publ. Astron. Soc. Pac. 106, 486 (1994)>
=1994PASP..106..486A 1994PASP..106..486A
ADC_Keywords: Clusters, open; Photometry, CCD
Abstract:
A CCD study of the peculiar open cluster, Melotte 66, on the
vbyHbeta system is presented. The V,(b-y) color-magnitude diagram of
this metal-deficient, old disk cluster confirms the anomalous features
found in photographic BV studies and extends the main sequence to
V=20. The main sequence exhibits a (b-y) color range significantly
larger than expected from photometric errors alone; the (b-y) colors
are correlated with Hbeta implying that the dispersion is real and is
not the result of variable reddening across the cluster. The m1 indices
for the turnoff stars imply a spread in [Fe/H] too small to explain
the color range. Though the subgiant region is poorly defined, the region
above the turnoff in the Hertzsprung gap is richly populated by a group
of "yellow stragglers" whose membership is confirmed by radial star counts
and radial velocities. The giant branch is richly populated but shows a
smaller spread in color at a given V than one would expect from the turnoff
region. More important, the giants exhibit a large scatter in m1, in
contradiction with the turnoff observations. Various explanations for these
observations are discussed, including CN variations among the giants triggered
by either binary evolution or rapid rotation among the main-sequence stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 99 520 Photometric indices for Mel 66 stars
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See also:
J/MNRAS/174/471 : Melotte 66 (Hawarden+, 1976)
J/A+A/283/911 : Abundances in NGC 2243 and Mel 66 (Gratton+ 1994)
J/A+A/488/943 : Abundances of giants in four Galactic clusters (Sestito+ 2008)
J/A+A/566/A39 : UBVI photometry of Melotte 66 (Carraro+, 2014)
Byte-per-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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2- 5 I4 --- Haw ?=0 Hawarden identification number (1)
7- 10 I4 --- ID [1/1458] Identification number
12- 17 F6.2 pix Xpos X position
19- 24 F6.2 pix Ypos Y position
28- 33 F6.3 mag Vmag [11/18] V magnitude (apparent)
36- 40 F5.3 mag e_Vmag rms uncertainty on V magnitude
43- 47 F5.3 mag b-y (b-y) color
50- 54 F5.3 mag e_b-y rms uncertainty on (b-y) color
56- 61 F6.3 mag m1 m1 index
64- 68 F5.3 mag e_m1 rms uncertainty on m1 index
71- 75 F5.3 --- Hbeta ? Hβ index
78- 82 F5.3 --- e_Hbeta ? rms uncertainty on Hbeta index
86- 87 I2 --- Ny [2/16] Number of y frames
89- 90 I2 --- Nb [1/17] Number of b frames
92- 93 I2 --- Nv [2/16] Number of v frames
95- 96 I2 --- Nw [0/20] Number of Hβ wide frames
98- 99 I2 --- Nn [0/11] Number of Hβ narrow frames
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Note (1): Hawarden T.G., 1976, MNRAS 243, 492 (J/MNRAS/243/492)
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Addresses:
Anthony-Twarog B.J. anthony (at) kuphsx.phsx.ukans.edu
Twarog B.A. twarog (at) kuphsx.phsx.ukans.edu
Sheeran M.
Department of Physics and Astronomy, University of Kansas,
Lawrence, Kansas 66045-2151
Origin: AAS CD-ROM series, Volume 2, 1994
(End) Lee Brotzman [ADS] 21-May-1994, Patricia Bauer [CDS] 03-Nov-1994