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The enigmatic WN8 stars: Intensive photometry of four southern stars on time scales from 30 min to 3 months
We present the first results of an extensive photometric study of themost intrinsically variable Wolf-Rayet (WR) stars: the WN8 subclass.Some 375 individual differential observations of WR16 and WR40 wereobtained over a contiguous interval of approximately 3 months in anarrow visual continuum bandpass. Over the same interval, we obtainedroughly 200 broadband V observations of the fainter WN8 stars WR66 andWR82. All four WN8 stars show significant random variability on timescales of hour to approximately a day -- probably related to thestochastic formation, propagation, and decay of emitting/scatteringinhomogeneities in the winds. Unlike for WR66 and WR82, the photometricbehavior of WR16 and WR40 is more deterministic with approximately twopossible periods in the range approximately 2-30 days -- possiblyrelated to some kind of Luminous Blue Variable (LBV), binary, orrotation phenomenon. In addition, WR82 shows a possible secular declineduring the 3 months and WR66 reveals a clear periodicity of 3.51 h. Thisshort period may be related to nonradial pulsations or a spiral-inbinary process invoking a low-mass, compact companion as seen in themassive x-ray binary Cyg X-3, a WN7 + c system of period 4.8 h.
| Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
| Long-term photometry of variables at ESO. I - The first data catalogue (1982-1986)
This paper presents the catalog of photometric data in the Stromgrensystem obtained during the first four years (October 1982 - September1986) of the Long-Term Photometry of Variables (LTPV) program at ESO.The data are available in computer-readable form.
| Stromgren photometry of the variable Wolf-Rayet star HD 86161 = WR 16
Stromgren uvby photometry of the Wolf-Rayet star WR 16 (HD 86161, WN 8)made in 1985/1986 is presented and discussed. The star appears to changeits brightness with a nonstable periodicity. Light variations arelargely due to continuum variations, while emission line variations playa minor role. Several possible explanations are offered.
| Radial velocities in three fields along the southern galactic equator
A list of radial velocities for 764 stars is given for three fields inthe Vela-Carina region of the galaxy. They were obtained from GPO-platestaken at La Silla and reduced following Fehrenbach's method.Slit-spectra were collected with the 152 cm-spectrographic telescope atLa Silla, to derive an accurate radial velocity for a sufficient numberof calibration stars: out of the 29 stars, 26 had no formerly publishedvalue. The global motions of 10 to 14 km/s can be considered as normalon the basis of galactic rotation. Some stars, however, show highvelocities, and are therefore marked with one or two asterisks in thetable.
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