J/AJ/109/817 Photometry of WN8 Stars (Antokhin+ 1995)
The Enigmatic WN8 Stars: Intensive Photometry of Four Southern Stars on Time
Scales From 30 min to 3 Months
Antokhin I., Bertrand J.-F., Lamontagne R., Moffat A.F.J., Matthews J.
<Astron. J. 109, 817 (1995)>
=1995AJ....109..817A 1995AJ....109..817A
ADC_Keywords: Stars, Wolf-Rayet; Photometry
Abstract:
We present the first results of an extensive photometric study of the
most intrinsically variable Wolf-Rayet stars: the WN8 subclass. Some
375 individual differential observations of WR16 and WR40 were obtained
over a contiguous interval of ∼3 months in a narrow visual continuum
bandpass. Over the same interval, we obtained roughly 200 broadband V
observations of the fainter WN8 stars WR66 and WR82. All four WN8
stars show significant random variability on time scales of hours to ∼a
day -- probably related to the stochastic formation, propagation, and
decay of emitting/scattering inhomogeneities in the winds. Unlike for
WR66 and WR82, the photometric behaviour of WR16 and WR40 is more
deterministic with ∼two possible periods in the range ∼2-30 days --
possibly related to some kind of LBV, binary, or rotation phenomenon.
In addition, WR82 shows a possible secular decline during the 3 months
and WR66 reveals a clear periodicity of 3.51 h. This short period may
be related to nonradial pulsations or a spiral-in binary process
invoking a low-mass, compact companion as seen in the massive x-ray
binary Cyg X-3, a WN7 + c system of period 4.8 h.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 8 Comparison stars for the WN8 stars
table2 33 367 Narrowband visual photometry for WR16
table3 33 381 Narrowband visual photometry for WR40
table4 33 219 Broadband visual photometry for WR66
table5 33 163 Broadband visual photometry for WR82
table.tex 69 9 LaTeX document to format tables 2, 3, 4, & 5
table2.tex 67 382 AASTeX version of Table 2
table3.tex 67 396 AASTeX version of Table 3
table4.tex 66 234 AASTeX version of Table 4
table5.tex 66 178 AASTeX version of Table 5
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- WR WR number
6-14 A9 --- Other Other name
15-20 F6.2 mag vmag []? v magnitude
21-25 F5.2 mag b-v []? b-v color
28-29 A2 --- Cmp Comparison star number (C1 or C2)
31-39 A9 --- Name Comparison star name
41-42 A2 --- Sp Spectral type
43-47 F5.1 mag Vmag V magnitude
48-55 F8.4 mag WR-C Difference between comparison and WR
56-63 F8.4 mag e_WR-C Error (sigma) in WR-C
64-71 F8.4 mag C2-C1 ? Difference between comparison star
72-79 F8.4 mag e_C2-C1 ? Error (sigma) in C2-C1
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Byte-by-byte Description of file: table2 table3 table4 table5
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.4 mag WR-C1 WR-C1 differential magnitude
21- 26 F6.4 mag WR-C2 WR-C2 differential magnitude
28- 33 F6.4 mag C2-C1 C2-C1 differential magnitude
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Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 26-Apr-1995
(JD completed at CDS)
(End) [CDS] 11-Jul-1995