A seven year campaign on WR 22

in Wolf-Rayet Stars: Binaries; Colliding Winds; Evolution. International Astronomical Union. Symposium no. 163 (1995)

Not Available

Photometric monitoring of Wolf-Rayet stars: Strömgren uvby and narrow-band photometry

in NATO ASIC Proc. 436: The Impact of Long-Term Monitoring on Variable Star Research: Astrophysics (1994)

Not Available

WR 134 line-profile variability revisited

in Astronomy and Astrophysics (1992), 256

Line profile variations of WR 134 are analyzed on more than 200 spectra collected at Haute Provence Observatory and at Kitt Peak National Observatory. No conclusive evidence is found for a periodic ... [more ▼]

Line profile variations of WR 134 are analyzed on more than 200 spectra collected at Haute Provence Observatory and at Kitt Peak National Observatory. No conclusive evidence is found for a periodic behavior. However, for some frequencies, for example, the ones close to nu = (n x 0.5)/d, the data are ill-distributed, and the existence of a related periodic phenomenon cannot be completely ruled out. This does not mean that the variability presents a purely random behavior. Several new characteristics of the observed deformations are extracted from the analysis of the spectra and it is tentatively suggested that these could be the signature of a bipolar flow. [less ▲]

Analysis of the light variations of the Wolf-Rayet star WR16

in Astronomy and Astrophysics. Supplement Series (1990), 84

This paper presents new data sets of Stromgren differential photometry observations of the Wolf-Rayet star WR16, collected at the ESO (La Silla, Chile). Results of detailed data analyses support previous ... [more ▼]

This paper presents new data sets of Stromgren differential photometry observations of the Wolf-Rayet star WR16, collected at the ESO (La Silla, Chile). Results of detailed data analyses support previous findings concerning the variability of WR16, with dominating power at frequencies below 1.5/d. The variations were found to be positively correlated on time lags up to about two days, a characteristic delay larger than the time of replacement of a typical WR star wind. A simple stochastic model is developed for the low frequency variability of the star, which is able to explain the available observations. [less ▲]

Analysis of the photometric variability of WR40

in Monthly Notices of the Royal Astronomical Society (1989), 238

New photometric data on the star WR40 are presented and, together with data already published, are analyzed in a detailed and homogeneous manner in order to investigate the variability of the star. Good ... [more ▼]

New photometric data on the star WR40 are presented and, together with data already published, are analyzed in a detailed and homogeneous manner in order to investigate the variability of the star. Good evidence is presented for the existence of a periodicity P = 6.250 + or - 0.078 day with a semiamplitude of 0.010 mag in the Stromgren b filter. Only part of the 0.1 mag peak-to-peak variation of the star can be explained in this way and other interesting features of the variability are outlined. The physical origin of the periodicity is discussed. [less ▲]

Which photometric period for WR 16?

in Astronomy and Astrophysics (1987), 185

Analysis of new and already published photometric observations shows that the Wolf-Rayet star WR 16 = HD 86161 is not a binary system (WR + compact, P = 5.365 d) as claimed by Moffat and Niemela (1982 ... [more ▼]

Analysis of new and already published photometric observations shows that the Wolf-Rayet star WR 16 = HD 86161 is not a binary system (WR + compact, P = 5.365 d) as claimed by Moffat and Niemela (1982). Instead it is shown that the simultaneous presence of two periodicities (about 1.3 and 2.5 days) is necessary to account for the observed variations during at least one observing run. The variability of the B9p star HD 86199, previously used as a comparison for a photometric study of WR 16, is established. [less ▲]

The possible appearance of a second period in the WN 5 star EZ Canis Majoris

in Astronomy and Astrophysics (1987), 178

Previously published photometric data on EZ Canis Majoris are reanalyzed. It is shown by different techniques that a sine-wave type periodicity close to one third of the claimed period of P = 3[SUP]d[/SUP ... [more ▼]

Previously published photometric data on EZ Canis Majoris are reanalyzed. It is shown by different techniques that a sine-wave type periodicity close to one third of the claimed period of P = 3[SUP]d[/SUP].766 may also be present in what was considered as peculiarities in the lightcurve. The data available do not allow to known if this second period is precisely equal or only close to one third of P nor if there is some dependence between the two. In any case, the mere possible existence of such a second period is an interesting fact in the discussion concerning the possible existence of non-radial pulsations in some WR stars. [less ▲]

Exercises in astronomy.

in Exercises in astronomy.. J. Kleczek (Editor).Revised and extended edition of "Practical work in elementary astronomy" by M. G. J. Minnaert. D. ReidelPublishing Co., Dordrecht, The Netherlands. 24+339 pp. Price Dfl. 140.00, US 64.00, £ 49.50 cloth; Dfl. 59.00, US 19.50, £ 18.00 paper (1987). ISBN 90-277-2409-1 cloth, ISBN 90-277-2423-7 paper. (1987)

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated ... [more ▼]

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated by the editor in collaboration with the contributing authors D. A. Allen, Z. Ceplechka, S. Ferraz Mello, K. J. Gordon, L. Houziaux, C. Jaschek, Z. Kopal, J. Manfroid, J. PalouÅ¡, J. Podolský, G. R. Quast, J. Surdej, A. B. Underhill, J. M. Vreux, D. G. Wentzel.The exercises are organized in the following sections:A. The planetary system: 1. Space and time, instruments. 2. The motions of celestial bodies. 3. Planets and satellites.B. The stars: 1. The Sun. 2. Stars and nebulae. 3. Stellar systems. [less ▲]

Photometry of the G8V Star HD 192020

in Information Bulletin on Variable Stars (1985), 2822

Not Available

Observations photographiques de la comète Kohoutek (1973 f) au grand télescope de Schmidt franco-liégeois

in Ciel et Terre (1974), 90

Not Available