J/A+AS/119/37 EZ CMa UBV & VBLUW photometry (Duijsens+, 1996)
Multi-colour photometric and spectroscopic monitoring of the WN5 star
EZ Canis Majoris
Duijsens M.F.J., van der Hucht K.A., van Genderen A.M., Schwarz H.E.,
Linders H.P.J., Kolkman O.M.
<Astron. Astrophys. Suppl. Ser. 119, 37 (1996)>
=1996A&AS..119...37D 1996A&AS..119...37D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Wolf-Rayet ; Photometry, Vilnius ; Photometry, UBV
Keywords: stars: Wolf-Rayet - stars: individual: WR 6 = HD 50896 = EZ CMa -
stars: variable - binaries: close
Description:
We present and analyse photometric and spectroscopic observations of
the WN5 star EZ Canis Majoris obtained over a period of 7 years. We
discuss the changing light curve, the shift in phase of the maxima and
point to flare type variability seen in one night. Small amplitude
variations are reported in another night. We have investigated the
change of the average visual magnitude over a time span of 18 years
and found a tentative cyclic variation with a time scale of
2425d (6.6yr) with a range of ∼0.07mag. This, of course, should be
verified. If true, a precession phenomenon may offer an explanation.
The trend of the maximum light amplitude of the 3.766d cycle is also
investigated and it shows a saw-tooth character with a timescale of
∼400d. A possible relation with the magnetic activity of the star is
discussed. We conclude that the line emission variability can be
caused by both a single star model with an ever-changing wind and a
binary (WN+NS) model.
Objects:
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RA (2000) DE Name
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06 54 12.97 -23 55 42.0 EZ CMa = WR 6 = HD 50896
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7 38 281 Relative Johnson magnitudes and colours of
January 11 1987 through January 16 1987
table13 56 408 *Relative VBLUW data of EZ CMa, epoch I
table21 56 218 *Relative VBLUW data of EZ CMa, epoch II
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Note to table13: Epoch I = November 25, 1988 through December 23, 1988
Note to table21: Epoch II= December 9, 1989 through December 12, 1989
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See also:
J/A+A/347/583 : EZ CMa spectroscopy (Georgiev+, 1999)
Byte-by-byte Description of file: table7
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocentric julian date
16- 20 F5.3 mag DVmag Relative V Johnson magnitude
24- 29 F6.3 mag DB-V Relative Johnson B-V color
33- 38 F6.3 mag DU-B Relative Johnson U-B color
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Byte-by-byte Description of file: table13 table21
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocentric julian date
14- 20 F7.4 mag DVmag Relative V magnitude (log intensity)
23- 29 F7.4 mag DBmag Relative B magnitude (log intensity)
32- 38 F7.4 mag DLmag Relative L magnitude (log intensity)
42- 47 F6.4 mag DUmag Relative U magnitude (log intensity)
51- 56 F6.4 mag DWmag Relative W magnitude (log intensity)
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Note: table7 corresponds to tables 7-12 of the printed version
table13 corresponds to tables 13-20 of the printed version
table21 corresponds to tables 21-25 of the printed version
Courtesy: M.F.J. Duijsens
(End) Patricia Bauer [CDS] 14-Feb-1996