J/A+AS/114/79 Polarimetry of Ap stars: general catalogue (Leroy+, 1995)
Linear polarimetry of Ap stars. V. A general catalogue of measurements
Leroy J.L.
<Astron. Astrophys. Suppl. Ser. 114, 79 (1995)>
=1995A&AS..114...79L 1995A&AS..114...79L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Ap; Polarization
Keywords: polarization - stars: magnetic fields - stars: chemically peculiar -
catalogs
Description:
A systematic program of broadband linear polarimetry, bearing on 55 Ap
stars, has been developed during the 4 last years, at the Pic du Midi
Observatory. While separate data have been already published, we
present in this paper a complete catalogue of our observational
material, including more than 400 measurements. We complement these
data with another 100 measurements, obtained previously by other
authors, so as to get a synthetic view of the phenomenon. Most of the
observations have been dedicated to a small number (15) of stars,
which show conspicuous changes of the linear polarization, so that it
is possible to know accurately the time variation of the Stokes
parameters: we expect that these new data will really improve our
knowledge of the magnetic configuration, after a proper analysis which
is currently being developed. For the other 40 stars, the polarization
is either too small, or strongly contaminated by the interstellar
polarization, so that broadband polarimetry is not very effective.
Anyway, this first systematic investigation on the linear polarization
of Ap stars will be a useful starting point for future measurements
which should be made with higher spectral resolution. Finally, our
measurements have provided new determinations of the rotation period
for several stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
polariz.dat 53 530 Polarization data (polariz.dat 1 to 68)
table69.dat 146 15 Fourier coefficients of the Q/I and U/I
expansion
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Byte-by-byte Description of file: polariz.dat
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Bytes Format Units Label Explanations
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2- 10 A9 --- Star Star name (1)
12- 14 A3 --- Filter Filter (2)
16- 25 F10.2 d JD Julian Date
27- 31 F5.3 % Pol Polarization degree
33- 35 I3 deg Theta Polarization orientation
37- 41 F5.3 % Q/I Reduced Stokes parameter Q/I
43- 48 F6.3 % U/I Reduced Stokes parameter U/I
50- 53 F4.3 % e_Q/I Standard deviation on Q/I and U/I
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Note (1): HD 11502 = γ Ari S
HD 11503 = γ Ari N
Note (2): the symbols are as follows:
B : B filter
Ba : B filter; Piirola and Tuominen 1981
Bb : B filter; Breger et al. 1989
Bc : B filter; Berdyugin et al. 1992
exB : extended-B filter; Kemp and Wolstencroft 1974
L : λ=4200A filter
L5 : λ=5200A filter
LB : λ=4200A or B filter
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Byte-by-byte Description of file: table69.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Star name
11- 15 F5.3 --- ZQ Fourier coefficient ZQ
17- 21 F5.3 --- AQ Fourier coefficient AQ
23- 27 F5.3 --- BQ Fourier coefficient BQ
29- 33 F5.3 --- CQ Fourier coefficient CQ
35- 39 F5.3 --- DQ Fourier coefficient DQ
41- 45 F5.3 --- EQ []? Fourier coefficient EQ
47- 51 F5.3 --- FQ []? Fourier coefficient FQ
53- 57 F5.3 --- GQ []? Fourier coefficient GQ
59- 63 F5.3 --- HQ []? Fourier coefficient HQ
65- 69 F5.3 --- IQ []? Fourier coefficient IQ
71- 75 F5.3 --- JQ []? Fourier coefficient JQ
78- 82 F5.3 --- ZU Fourier coefficient ZU
84- 88 F5.3 --- AU Fourier coefficient AU
90- 94 F5.3 --- BU Fourier coefficient BU
96-100 F5.3 --- CU Fourier coefficient CU
102-106 F5.3 --- DU Fourier coefficient DU
108-112 F5.3 --- EU []? Fourier coefficient EU
114-118 F5.3 --- FU []? Fourier coefficient FU
120-124 F5.3 --- GU []? Fourier coefficient GU
126-130 F5.3 --- HU []? Fourier coefficient HU
132-136 F5.3 --- IU []? Fourier coefficient IU
138-142 F5.3 --- JU []? Fourier coefficient JU
144-146 F3.1 --- Chi2/nu Ratio of Chi-squared to the number of degrees
of freedom
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References:
Berdyugin A., Breger M., Polosukhina N., =1992A&A...255..149B 1992A&A...255..149B
Breger M., Weiss W.W., Wills B.J., =1989A&A...215...48B 1989A&A...215...48B
Kemp J.C., Wolstencroft R.D., =1974MNRAS.166....1K 1974MNRAS.166....1K
Piirola V., Tuominen I., 1981 in: Upper main sequence CP stars,
23rd Liege Astrophys. Coll., Universite de Liege, p 283
(End) Simona Mei [CDS] 05-Jul-1995