J/other/AstBu/62.244 Magnetic field in CP stars (Glagolevskij, 2007)
Magnetic field dependence of chemical anomalies in CP stars.
Glagolevskij Yu.V.
<Astrophys. Bull., 62, 244-256 (2007)>
=2007AstBu..62..244G 2007AstBu..62..244G
ADC_Keywords: Stars, peculiar ; Magnetic fields
Abstract:
The dependence of the degree of anomaly of parameter Z of Geneva
photometry (Z0=ZCP-Znorm) on the average surface magnetic field Bs
is analyzed. The Z0 value is proportional to the degree of anomaly of
chemical composition. It was found that Bs-->0 corresponds
Z0-->-0.010/-0.015, i.e., part of CP stars are virtually devoid of
magnetic field, but exhibit chemical anomalies. This effect may be due
to selection whereby only objects with strong chemical anomalies are
classified as CP stars, thereby producing a deficit of stars with
relatively weak anomalies. Moreover, CP stars have other sources of
stabilization of their atmospheres besides the magnetic field, e.g.,
slow rotation. Formulas relating Z0 to Bs are derived.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 32 37 Parameters Z0, which characterizes the intensity of
the λ5200Å depression, and ΔX, which
characterizes the degree of chemical anomalies
table3.dat 41 85 Data for deriving the Z0-Bs relation for Bs values
determined from line splitting (in kG)
table4.dat 43 250 Data for deriving the Bs-Z0 relation with Bs
determined from the relation
Bs=(5.6±0.6)(<Be>-(0.16±0.12))
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number
8- 13 A6 --- Type Spectral type peculiarities
15- 19 I5 K Te Effective temperature
21- 26 F6.3 mag Z0 Parameter Z0, which characterizes the intensity
of the λ5200Å depression (1)
28- 32 F5.2 --- DeltaX Parameter which characterizes the degree of
chemical anomalies (2)
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Note (1): Z0=Z(CP)-Z(norm),
where Z(CP) is the parameter Z of Geneva photometry for CP stars,
and Z(norm) the parameter Z of Geneva photometry of normal stars.
Z is defined, in Cramer & Mader (1979A&A....78..305C 1979A&A....78..305C), as
Z=-0.4572+0.0255*U-0.1740*B1+0.4606*B2-1.1205*V1+0.7994*G
Note (2): DeltaX=(0.42±0.12)-(15.34±4.05)Z0
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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- 6 I6 --- HD HD number
8- 11 F4.1 dT Bs ?=- Average surface magnetic field value (1)
13- 15 F3.1 dT Bs(P) ?=- Bs value from Preston
(1971ApJ...164..309P 1971ApJ...164..309P) (2)
17- 20 F4.1 dT Bs(G) ?=- Bs value from Glagolevskij et al.
(1986AISAO..23...37G 1986AISAO..23...37G) (3)
22- 26 I5 K Te Temperature
27 A1 --- u_Te Uncertainty flag on Te
29- 34 F6.3 mag Z0 Z0 parameter (4)
36- 41 A6 --- Type Spectral type peculiarities
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Note (1): We adopted the Bs values from the catalog of Romanyuk (2000, in
Magnetic fields of chemically peculiar and related stars, Ed. by
Yu.V. Glagolevskij and I.I. Romanyuk (Moscow, 2000), p.20.).
Unit of magnetic field is kilo-Gauss (CGS) or deci-Tesla (SI).
Note (2): We adopted the Bs(P) values from the the paper by Preston
(1971ApJ...164..309P 1971ApJ...164..309P).
Note (3): The Bs(G) values estimated by Glagolevskij et al.
(1986AISAO..23...37G 1986AISAO..23...37G) from the Stibbs-Preston formula for stars with
known phase dependences of variations of magnetic field Bs(P).
Note (4): We computed all the Z values both for normal and peculiar stars
by applying the formula from Cramer and Maeder (1979A&A....78..305C 1979A&A....78..305C)
to the data from the catalog of Rufener (1988, Cat. II/169).
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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- 6 I6 --- HD HD number
8- 12 I5 10-4T <Be> ?=- Mean effective magnetic fields value (Gauss)
13 A1 --- u_<Be> Uncertainty flag on <Be>
15- 18 F4.1 kgauss Bs ?=- Average surface magnetic field value
19 A1 --- u_Bs Uncertainty flag on Bs
21- 26 F6.3 mag Z0 Z0 parameter
28- 32 I5 K Te Temperature
33 A1 --- u_Te Uncertainty flag on Te
35- 43 A9 --- Type Spectral type peculiarities
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Jul-2008