J/A+A/566/A132 Teff and L for stars in 7 open clusters (Silaj+, 2014)
Accurate age determinations of several nearby open clusters containing
magnetic Ap stars.
Silaj J., Landstreet J.D.
<Astron. Astrophys., 566, A132-132 (2014)>
=2014A&A...566A.132S 2014A&A...566A.132S
ADC_Keywords: Clusters, open ; Effective temperatures
Keywords: stars: chemically peculiar - Hertzsprung-Russell and C-M diagrams -
open clusters and associations: general - stragglers blue
Abstract:
To study the time evolution of magnetic fields, chemical abundance
peculiarities, and other characteristics of magnetic Ap and Bp stars
during their main sequence lives, a sample of these stars in open
clusters has been obtained, as such stars can be assumed to have the
same ages as the clusters to which they belong. However, in exploring
age determinations in the literature, we find a large dispersion among
different age determinations, even for bright, nearby clusters.
Our aim is to obtain ages that are as accurate as possible for the
seven nearby open clusters α Per, Coma Ber, IC 2602, NGC 2232,
NGC 2451A, NGC 2516, and NGC 6475, each of which contains at least one
magnetic Ap or Bp star. Simultaneously, we test the current
calibrations of Te and luminosity for the Ap/Bp star members, and
identify clearly blue stragglers in the clusters studied.
We explore the possibility that isochrone fitting in the theoretical
Hertzsprung-Russell diagram (i.e. log(L/L☉) vs. logTe), rather
than in the conventional colour-magnitude diagram, can provide more
precise and accurate cluster ages, with well-defined uncertainties.
Description:
This paper investigates seven nearby open clusters: α Per,
Coma Ber, IC 2602, NGC 2232, NGC 2451A, NGC 2516, and NGC 6475. The
clusters studied are listed in Table 1 and Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 73 7 Basic data for clusters studied and ages
table3.dat 85 235 Cluster members
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See also:
J/A+A/345/471 : Memberships of open clusters (Robichon+, 1999)
J/A+AS/146/251 : Open clusters absolute proper motions. I. (Baumgardt+, 2000)
J/A+A/376/441 : Absolute proper motions of 112 open clusters (Dias+, 2001)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Cluster Cluster name
11- 15 F5.2 arcsec plx Mean parallax
17- 20 F4.2 arcsec e_plx rms uncertainty in plx
22- 25 F4.2 mag DM True distance modulus
27- 30 F4.2 mag e_DM rms uncertainty on DM
32- 36 F5.1 pc Dist Distance
38- 41 F4.2 mag E(B-V) Mean colour excess
43- 46 F4.2 mag e_E(B-V) rms uncertainty on E(B-V)
48- 52 F5.2 [Sun] [Fe/H] Mean abundance log(NFe/NH)
(log(NFe☉/N_H☉=[Fe/H])
54- 57 F4.2 [Sun] e_[Fe/H] rms uncertainty on [Fe/H]
59- 63 F5.3 --- Z Deduced heavy element mass fraction
65- 68 F4.2 [yr] logt Cluster age
70- 73 F4.2 [yr] e_logt rms uncertainty on age
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Cluster Cluster name
11- 16 I6 --- HIP ? HIP number of star
19- 49 A31 --- Name Other name(s) of star
52- 57 F6.3 mag VMag [-4.7/5.3] Absolute V magnitude
59- 64 F6.3 mag (B-V)0 ? Deredenned B-V colour index
67- 71 I5 K Teff [3820/30020]? Effective temperature
73- 77 F5.3 [K] logTeff [3.58/4.477]? log of effective temperature
79- 84 F6.3 [Lsun] logL ? Luminosity
85 A1 --- Note [abc] Nature of star: a=Ap (magnetic star);
b=binary star; c=blue straggler
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Oct-2014