J/A+A/395/823 CCD Δa-photometry of 5 open clusters (Paunzen+, 2002)
CCD photometric search for peculiar stars in open clusters.
IV. Collinder 272, Pismis 20, Lynga 14, NGC 6396 and NGC 6611
Paunzen E., Maitzen H.M.
<Astron. Astrophys. 395, 823 (2002)>
=2002A&A...395..823P 2002A&A...395..823P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, narrow-band
Keywords: stars: chemically peculiar - stars: early-type -
techniques: photometric - open clusters and associations: general
Abstract:
The time scale on which chemical peculiarity in upper main sequence
stars begins is unknown. Results from the Hipparcos measurements
indicate that the classical chemically peculiar (CP) stars occupy the
whole area from the zero age main sequence to the terminal age main
sequence. Hubrig et al. (2000ApJ...539..352H 2000ApJ...539..352H) reported that the
magnetic fields appear only in stars that have already completed at
least approximately 30% of their main sequence life time. Previous
observations in the very young Orion OB1 and Scorpio Centaurus
associations reveal a percentage of chemically peculiar stars that is
significantly smaller (less than 5%) than that of the galactic field
(up to 25%). This already indicates that the phenomenon needs at least
several Myr to appear. Since no further observations have been
published since then, we have observed the five very young
(1Myr<Age<25Myr) open clusters Collinder 272, Pismis 20, Lynga 14, NGC
6396 and NGC 6611. Photometry from 250 CCD frames in the three filter
Delta a-system results in very low detection limits (0.008 to
0.015mag). We find no single photometrically chemically peculiar
candidate in approximately 460 observed cluster members in the five
program clusters. From the number of observed objects we deduce upper
limits between 0.6% and 2.4% for the incidence of CP stars for the
five observed aggregates.The tables presented here include all
photometric observations of these five clusters.
For a description of the (Delta a) photometric system, see e.g.
GCPD/75: a = g2 - (g1+y)/2 g1 and g2 centered at 502 and 524nm.
Objects:
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RA (2000) DE Designation(s)
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13 30 36. -61 16 00 Cl Collinder 272
15 15 24. -59 04 00 Cl Pismis 20
16 55 00.8 -45 20 00 Cl Lynga 14
17 38 06. -35 00 00 NGC 6396
18 18 48. -13 47 00 NGC 6611
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 75 111 Observed program stars of Collinder 272
table5.dat 80 238 Observed program stars of Pismis 20
table6.dat 72 53 Observed program stars of Lynga 14
table7.dat 71 105 Observed program stars of NGC 6396
table8.dat 85 79 Observed program stars of NGC 6611
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See also:
J/A+A/371/L5 : CCD Δa-photometry of NGC 1866 (Maitzen+, 2001)
J/A+A/373/153 : NGC 2489, 2567, 2658, 5281 and 6208 (Paunzen+, 2001)
J/A+A/385/867 : NGC 2439, 3960, 6134, 6192 and 6451 (Paunzen+, 2002)
J/A+A/412/721 : NGC 2099, 3114, 6204, 6705 and 6756 (Paunzen+, 2003)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Number in Collinder 22, sorted after X and Y
Cl* Collinder 272 PPM NNN in Simbad
5- 7 I3 --- WEBDA ? Notation according to WEBDA
(Cl* Collinder 272 VBF NNN in Simbad)
9- 13 F5.1 pix Xpos X-coordinate
15- 19 F5.1 pix Ypos Y-coordinate
21- 26 F6.3 mag Vmag Mean V value
28- 32 F5.3 mag a Mean a index (Maitzen)
34- 38 F5.3 mag e_a Sigma a
40- 45 F6.3 mag g1-y Mean (g1-y) index
47- 51 F5.3 mag e_g1-y Sigma (g1-y)
53- 61 E9.3 mag da(g1-y) Deviation from cluster line (Delta a)
62- 65 F4.2 mag B-V ? (B-V) from the literature
67- 72 F6.3 mag da(B-V) ? Deviation from cluster line (Delta a)
74- 75 I2 --- Obs Number of observations
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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- 3 I3 --- Seq Number in Pismis 20, sorted after X and Y
Cl* Pismis 20 PPM NNN in Simbad
5- 8 I4 --- WEBDA ? Notation according to WEBDA
10- 14 F5.1 pix Xpos X-coordinate
16- 20 F5.1 pix Ypos Y-coordinate
22- 27 F6.3 mag V0 Mean V0 value
29- 33 F5.3 mag acorr Mean a(corr) index (Maitzen)
35- 39 F5.3 mag e_acorr Sigma a(corr)
41- 46 F6.3 mag (g1-y)0 Mean (g1-y)0 index
48- 52 F5.3 mag e_(g1-y)0 Sigma (g1-y)0
54- 59 F6.3 mag da(g1-y)0 Deviation from cluster line (Delta a)
61- 65 F5.2 mag (B-V)0 ? (B-V)0 from the literature
67- 72 F6.3 mag da(B-V0) ? Deviation from cluster line (Delta a)
74- 77 F4.2 mag E(B-V) Reddening
79- 80 I2 --- Obs Number of observations
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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- 3 I3 --- Seq Number in Lynga 14, sorted after X and Y
Cl* Lynga 14 PPM NNN in Simbad
5- 8 I4 --- WEBDA ? Notation according to WEBDA
(Cl* Lynga 14 NNN in Simbad)
10- 14 F5.1 pix Xpos X-coordinate
16- 20 F5.1 pix Ypos Y-coordinate
22- 27 F6.3 mag V0 Mean V0 value
29- 33 F5.3 mag acorr Mean a(corr) index
35- 39 F5.3 mag e_acorr Sigma a(corr)
41- 46 F6.3 mag (g1-y)0 Mean (g1-y)0 index
48- 52 F5.3 mag e_(g1-y)0 Sigma (g1-y)0
54- 59 F6.3 mag da(g1-y)0 Deviation from cluster line (Delta a)
61- 64 F4.2 mag (B-V)0 ? (B-V)0 from the literature
66- 69 F4.2 mag E(B-V) reddening
71- 72 I2 --- Obs Number of observations
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Number in NGC 6369, sorted after X and Y
Cl* NGC 6369 PPM NNN in Simbad
5- 6 I2 --- MV ? Notation according to Moffat & Vogt
(1975A&AS...20..155M 1975A&AS...20..155M, NGC 6396 NN)
8- 12 F5.1 pix Xpos X-coordinate
14- 18 F5.1 pix Ypos Y-coordinate
20- 25 F6.3 mag V0 Mean V0 value
27- 31 F5.3 mag acorr Mean a(corr) index (Maitzen)
33- 37 F5.3 mag e_acorr Sigma a(corr)
39- 44 F6.3 mag (g1-y)0 Mean (g1-y)0 index
46- 50 F5.3 mag e_(g1-y)0 Sigma (g1-y)0
52- 57 F6.3 mag da(g1-y)0 Deviation from cluster line (Delta a)
59- 63 F5.2 mag (B-V)0 ? (B-V)0 from the literature
65- 68 F4.2 mag E(B-V) reddening
70- 71 I2 --- Obs Number of observations
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Number in NGC 6611, sorted after X and Y
Cl* NGC 6611 PPM NNN in Simbad
4- 8 I5 --- BKP ? Notation according to Belikov et al. (1999,
Cat. J/A+AS/134/525, Cl* NGC 6611 BKP NNNNN)
10- 12 I3 --- No3 ? Notation according to WEBDA
(NGC 6611 NNN in Simbad)
14- 18 F5.1 pix Xpos X-coordinate
20- 24 F5.1 pix Ypos Y-coordinate
26- 31 F6.3 mag V0 Mean V0 value
33- 37 F5.3 mag acorr Mean a(corr) index (Maitzen)
39- 43 F5.3 mag e_acorr Sigma a(corr)
45- 50 F6.3 mag (g1-y)0 Mean (g1-y)0 index
52- 56 F5.3 mag e_(g1-y)0 Sigma (g1-y)0
58- 63 F6.3 mag da(g1-y)0 Deviation from cluster line (Delta a)
65- 70 F6.3 mag (B-V)0 ? (B-V)0 from the literature
72- 77 F6.3 mag da(B-V)0 ? Deviation from cluster line (Delta a)
79- 82 F4.2 mag E(B-V) reddening
84- 85 I2 --- Obs Number of observations
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Acknowledgements: Ernst Paunzen
References:
Bayer et al., Paper I 2000A&AS..147...99B 2000A&AS..147...99B
Paunzen & Maitzen, Paper II 2001A&A...373..153P 2001A&A...373..153P, Cat. J/A+A/373/153
Paunzen & Maitzen, Paper III 2002A&A...385..867P 2002A&A...385..867P, Cat. J/A+A/385/867
(End) Patricia Bauer [CDS] 22-Nov-2002