J/A+A/489/911 Polarimetric measures of selected variable stars (Elias+, 2008)
Polarimetric measures of selected variable stars.
Elias N.M.II, Koch R.H., Pfeiffer R.J.
<Astron. Astrophys. 489, 911 (2008)>
=2008A&A...489..911E 2008A&A...489..911E
ADC_Keywords: Stars, variable ; Polarization
Keywords: polarization - binaries: close - Cepheids - circumstellar matter -
accretion, accretion disks - dust, extinction
Abstract:
The purpose of this paper is to summarize and interpret unpublished
optical polarimetry for numerous program stars that were observed over
the past decades at the Flower and Cook Observatory (FCO), University
of Pennsylvania. We also make the individual calibrated measures
available for long-term comparisons with new data.
We employ three techniques to search for intrinsic variability within
each dataset. First, when the observations for a given star and filter
are numerous enough and when a period has been determined previously
via photometry or spectroscopy, the polarimetric measures are plotted
versus phase. If a statistically significant pattern appears, we
attribute it to intrinsic variability. Second, we compare means of the
FCO data to means from other workers. If they are statistically
different, we conclude that the object exhibits long-term intrinsic
variability. Third, we calculate the standard deviation for each
program star and filter and compare it to the standard deviation
estimated from comparable polarimetric standards. If the standard
deviation of the program star is at least three times the value
estimated from the polarimetric standards, the former is considered
intrinsically variable. All of these statements are strengthened when
variability appears in multiple filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 57 39 Stars positions (from Simbad)
table12.dat 84 71 *The weighted means of the normalized linear and
circular polarisations, together with the reduced
standard deviations and numbers of observations
table.dat 58 670 Polarization observations of close binary and
β Cep stars from the polarization program
at the Flower and Cook Observatory, University
of Pennsylvania.
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Note on table12.dat: Normalized Linear / Circular Stokes parameters.
The reduced standard deviations must be multiplied by the square
root of the number of measurements to compare them with the
standard-deviation equations.
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Simbad star name
11- 12 I2 h RAh Simbad Hour of Right Ascension (J2000.0)
14- 15 I2 min RAm Simbad Minute of Right Ascension (J2000.0)
17- 20 F4.1 s RAs Simbad Second of Right Ascension (J2000.0)
22 A1 --- DE- Simbad Sign of the Declination (J2000.0)
23- 24 I2 deg DEd Simbad Degree of Declination (J2000.0)
26- 27 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0)
29- 30 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0)
33- 38 F6.3 mag Bmag ? Simbad B band magnitude
40- 44 F5.3 mag Vmag Simbad V band magnitude
46- 57 A12 --- SpType Simbad MK spectral type
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Byte-by-byte Description of file: table12.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
13- 21 A9 --- Star Other name (HD name if exist)
23- 24 A2 --- Filt [UBVRB1B2 -] Filter (G1)
26- 32 F7.4 % q Weighted mean q Stokes parameter
34- 39 F6.4 % e_q ? rms uncertainty on q
41- 46 F6.3 % u Weighted mean u Stokes parameter
48- 52 F5.3 % e_u ? rms uncertainty on u
54- 55 I2 --- Nl Number of observations for linear polarisation
57- 63 F7.4 % v ? Weighted mean v Stokes parameter
65- 70 F6.4 % e_v ? rms uncertainty on v
72- 73 I2 --- Nc Number of observations for circular polarisation
75- 84 A10 --- Note Note on observation
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Name (HD name if exist)
10- 11 A2 --- n_Star [-6 ] Multiplicity index for the binary HD 036485-6
13- 23 F11.3 d HJD Heliocentric Julian date
25 A1 --- Filt [UBVR-] Filter (G1)
27- 32 F6.3 % q Normalized linear q Stokes parameter (NLSP)
34- 39 F6.3 % u Normalized linear u Stokes parameter (NLSP)
41- 45 F5.3 % e_q ? Normalized rms uncertainty on q and u (NLSP error)
47- 52 F6.3 % v ? Normalized circular v Stokes parameter (NCSP)
54- 58 F5.3 % e_v ? Normalized rms uncertainty on v (NCSP error) (2)
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Note (2): No data for v parameter indicates no concurrent NCSP measurement
with the NLSP measurement.
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Global notes:
Note (G1): - for unfiltered (≃ wide-band green).
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Acknowledgements:
Nicholas Elias,
(End) Patricia Vannier [CDS] 03-Oct-2008