J/AJ/150/200 Photometry and spectroscopy of stars in Cz 30 (Hayes+, 2015)
Properties of the old open cluster Czernik 30.
Hayes C.R., Friel E.D., Slack T.J., Boberg O.M.
<Astron. J., 150, 200 (2015)>
=2015AJ....150..200H 2015AJ....150..200H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Equivalent widths ;
Radial velocities ; Effective temperatures ; Abundances, [Fe/H]
Keywords: open clusters and associations: individual (Cz 30)
Abstract:
We present new photometric and spectroscopic data of the old open
cluster Czernik 30. Wide field BVI photometry allows us to correct for
the high field contamination by statistical subtraction to produce a
color-magnitude diagram (CMD) that clearly reveals the cluster
sequence. From spectra of stars in the cluster field obtained with the
Hydra spectrograph on the Wisconsin-Indiana-Yale-NOAO 3.5m telescope
we determine a mean cluster velocity of +79.9±1.5km/s and provide
membership information that helps further define the cluster giant
branch and red clump. Stellar abundances for the brighter giants in
the cluster indicate a mean metallicity of [Fe/H]=-0.2±0.15. Fitting
theoretical isochrones to the CMD we determine the following
properties of Czernik 30: age=2.8±0.3Gyr, (m-M)v=14.8±0.1,
E(B-V)=0.24±0.06, and E(V-I)=0.36±0.04. Czernik 30 is an old,
sub-solar metallicity cluster located at a Galactocentric radius of
Rgc∼13.3kpc. Given its age and position just beyond the transition
to a flat abundance gradient seen in the open cluster population,
Czernik 30 provides an interesting target for future observations.
Description:
Cz 30 was observed using the Wisconsin-Indiana-Yale-NOAO (WIYN) 0.9m
telescope with the S2KB imager, a 2048*2048 pixel CCD, with a pixel
scale of 0.6"/pixel providing a total field of view of 20.5'*20.5'.
Observations were taken on 2012 February 17 in B, V, and I filters
with a typical seeing of about 1.5" and the CCD centered near the
cluster center. We present our set of photometry in Table3.
Cz 30 was also observed with the Hydra multi-object fiber positioner
and Bench Spectrograph on the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m
telescope. The cluster was observed on 2014 January 18 and 19 and
February 14 (UT) in the echelle mode, giving a dispersion of
0.16Å/pixel and covering the range of ∼6060-6380Å. Table4 gives
the results of velocity determinations for stars in Cz 30.
Table5 gives lines used along with the measured equivalent widths. We
obtained [Fe/H] estimates for 10 stars, whose final atmospheric
parameters and abundances are given in Table6.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 92 6294 Photometric data
table4.dat 34 73 Individual stellar velocities and membership
table5.dat 86 37 Linelist and equivalent widths
table6.dat 37 10 Stellar parameters and metallicities
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See also:
B/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)
J/PAZh/38/571 : Astrophysical parameters for 593 open clusters (Gozha+, 2012)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star [1/6294] Star identification number
6- 13 F8.3 pix Xpix [2.4/2045.4] Pixel position in Right Ascension
15- 22 F8.3 pix Ypix [2.4/2048.8] Pixel position in Declination
24- 25 I2 h RAh Hour of Right Ascension (J2000)
27- 28 I2 min RAm Minute of Right Ascension (J2000)
30- 34 F5.2 s RAs Second of Right Ascension (J2000)
36 A1 --- DE- Sign of the Declination (J2000)
37- 38 I2 deg DEd Degree of Declination (J2000)
40- 41 I2 arcmin DEm Arcminute of Declination (J2000)
43- 47 F5.2 arcsec DEs Arcsecond of Declination (J2000)
49- 54 F6.3 mag Vmag [10.9/23] The V band magnitude
56- 61 F6.4 mag e_Vmag [0.003/0.555] Error in Vmag
63- 69 F7.4 mag B-V [-4.26/8.336]? The (B-V) color index
71- 77 F7.4 mag e_B-V [0.005/0.766]? Error in B-V
79- 85 F7.4 mag V-I [-4.007/6.087] The (V-I) color index
87- 92 F6.4 mag e_V-I [0.006/0.73] Error in V-I
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star [158/6290] Star identification number
6- 9 I4 --- WEBDA [1/1674]? WEBDA identification number (1)
11- 16 F6.3 mag Vmag [13.7/17] The V band magnitude
18- 22 F5.3 mag B-V [0.5/4.3] The (B-V) color index
24- 29 F6.2 km/s RV [0.4/160.4] Radial velocity
31- 34 A4 --- Mm Member? (Yes or No)
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Note (1): Piatti et al. (2009NewA...14...97P 2009NewA...14...97P).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda [6079/6358.7] Wavelength λ (in Å)
10- 13 A4 --- Ion Species identifier (FeI or FeII)
15- 19 F5.3 eV EP [0.859/4.733] Excitation potential
21- 26 F6.3 [-] loggf [-6/-0.72] Log oscillator strength
28- 32 F5.1 0.1pm EW343 [44.3/186.1]? Equivalent width in Star 343 (1)
34- 38 F5.1 0.1pm EW695 [40.4/176.9]? Equivalent width in Star 695 (1)
40- 44 F5.1 0.1pm EW732 [27.1/186.7]? Equivalent width in Star 732 (1)
46- 50 F5.1 0.1pm EW946 [73.3/172.3]? Equivalent width in Star 946 (1)
52- 56 F5.1 0.1pm EW2343 [67.9/157.8]? Equivalent width in Star 2343 (1)
58- 62 F5.1 0.1pm EW2482 [49.2/169.8]? Equivalent width in Star 2482 (1)
64- 68 F5.1 0.1pm EW3672 [44.5/192.6]? Equivalent width in Star 3672 (1)
70- 74 F5.1 0.1pm EW4175 [39.8/197.5]? Equivalent width in Star 4175 (1)
76- 80 F5.1 0.1pm EW4517 [60.6/170.5]? Equivalent width in Star 4517 (1)
82- 86 F5.1 0.1pm EW6248 [58.7/196]? Equivalent width in Star 6248 (1)
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Note (1): In units of mÅ.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star [343/6248] Star identification number
6- 9 I4 K Teff [4350/4800] Effective temperature
11- 13 F3.1 [cm/s2] logg [1.5/2.2] Log of surface gravity
15- 18 F4.2 km/s Vt [1.2/1.26] Microturbulent velocity
20- 21 I2 --- Nl [16/27] Number of lines
23- 27 F5.2 [Sun] [Fe/H] [-0.42/0.14] Metallicity
29- 32 F4.2 [Sun] s_[Fe/H] [0.21/0.32] The rms dispersion about the mean
metallicity (σ)
34- 37 F4.1 km/s RV [74.2/81.2] Radial velocity
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 13-Jun-2016