References of "Astronomy and Astrophysics. Supplement Series"
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See detailListe des étoiles Ap et Am dans des amas ouverts
Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1988), 76

We have established a catalogue of the stars that are in the field of open clusters among all those which appear in the general catalogue of Ap and Am stars.

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See detailThe eclipsing binary system HD208496
van Hamme, W.; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1988), 74

New photoelectric observations of the 6th magnitude suspected eclipsing binary system HD 208496 are presented. A Wilson-Devinney light curve solution reveals a detached system with components approaching ... [more ▼]

New photoelectric observations of the 6th magnitude suspected eclipsing binary system HD 208496 are presented. A Wilson-Devinney light curve solution reveals a detached system with components approaching the terminal age main sequence. The orbital period is suspected to be variable. [less ▲]

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See detailStudy of AG Carinae. I - The 1977 spectrum of the star
Hutsemekers, Damien ULg; Kohoutek, L.

in Astronomy and Astrophysics. Supplement Series (1988), 73

Spectroscopic observations of the variable P Cygni-like star AG Car have been obtained in February 1977. At this epoch, the star was in a relative minimum phase (V = 7.6) observed during a long and ... [more ▼]

Spectroscopic observations of the variable P Cygni-like star AG Car have been obtained in February 1977. At this epoch, the star was in a relative minimum phase (V = 7.6) observed during a long and comparatively quiet period of intermediate brightness. The spectrum displays prominent P Cygni lines of He I, Si III, N II and Fe III. The corresponding equivalent spectral type is B2-3 Ib. The presence of an outward accelerated envelope with a multiple shell structure is confirmed. The observation of broad [Fe II] emission lines, in contrast with the absence of permitted ones, implies the presence of a low density shell expanding at about 200 km/s. [less ▲]

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See detailFirst supplement to the catalog of observed periods of AP stars
Catalano, F. A.; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1988), 72

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity ... [more ▼]

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity was known before 1983 but they were not reported in the previous catalogue. Recently attributed variable star names are also reported. [less ▲]

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See detailPremier supplément au catalogue des périodes observées our des étoiles Ap
Catalano, F. A.; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1988), 72

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity ... [more ▼]

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity was known before 1983 but they were not reported in the previous catalogue. Recently attributed variable star names are also reported. [less ▲]

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See detailInstrumental effects and the Stroemgren photometric system
Manfroid, Jean ULg; Sterken, C.

in Astronomy and Astrophysics. Supplement Series (1987), 71

The extent to which the use of different photometers can affect results on stellar color indices was investigated by simultaneously observing a sample of widely different stars with several uvby ... [more ▼]

The extent to which the use of different photometers can affect results on stellar color indices was investigated by simultaneously observing a sample of widely different stars with several uvby photometric systems available at the ESO, La Silla, Chile. In one instance, the ESO 50-cm telescope and the four-channel photometer at the Danish 50-cm telescope were used simultaneously. The reductions were performed separately on each data set, using a linear color transformation procedure. The results agree with theoretical investigations which showed that substantial errors can arise from the nonconformity of passbands. It is emphasized that it is necessary to use separate color transformations for various stellar types and classes and for different interstellar reddenings. [less ▲]

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See detailPhotometric variability of some CP stars
Heck, A.; Mathys, G.; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1987), 70

The photometric data relative to twenty-three southern CP stars have been re-analysed. New or improved parameters of the lightcurves are presented for eleven of them.

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See detailUVBY observations of A, F, G and K field stars
Manfroid, Jean ULg; Oblak, E.; Pernier, B.

in Astronomy and Astrophysics. Supplement Series (1987), 69

Photoelectric data in the uvby system have been obtained for about 800 southern stars of the Hipparcos Input Catalog (Grenon, 1982, 1985). Most of the stars are F and G main sequence and fall in the ... [more ▼]

Photoelectric data in the uvby system have been obtained for about 800 southern stars of the Hipparcos Input Catalog (Grenon, 1982, 1985). Most of the stars are F and G main sequence and fall in the magnitude range V = 8-11. [less ▲]

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See detailThe ultraviolet spectrum of the peculiar emission-line star GG Carinae - The line identifications
Brandi, E.; Gosset, Eric ULg

in Astronomy and Astrophysics. Supplement Series (1987), 68

Line features as well as the continuum of GG Carinae in the ultraviolet wavelength domain were described by Brandi et al. (1986) on the basis of a series of high and low resolution IUE spectra for which ... [more ▼]

Line features as well as the continuum of GG Carinae in the ultraviolet wavelength domain were described by Brandi et al. (1986) on the basis of a series of high and low resolution IUE spectra for which the line identifications are detailed here. The present contribution is thus the complement to the above-mentioned paper and enables the disentangling of the complex and rich spectrum of GG Carinae. [less ▲]

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See detailBW Vulpeculae - A coordinated campaign of photoelectric photometry from thirteen observatories
Sterken, C.; Snowden, M.; Africano, J. et al

in Astronomy and Astrophysics. Supplement Series (1986), 66

This paper contains the fully reduced observational data on the Beta Cep star BW Vul, which were obtained in the summer of 1982 during an international campaign at thirteen observatories in the northern ... [more ▼]

This paper contains the fully reduced observational data on the Beta Cep star BW Vul, which were obtained in the summer of 1982 during an international campaign at thirteen observatories in the northern hemisphere. Useful measurements were made during a total of 486 hours. All observations have been assigned proper weights and were binned in time intervals of 90 seconds. In this manner the observations were combined into single data points which resulted in about 6000 mean differential measurements. A preliminary ephemeris for 1982 is derived, and a mean lightcurve is given. The results indicate a fair degree of stability in the shape and in the amplitude of the lightcurve. Possible variations exist in the morphology of the stillstand phenomenon. [less ▲]

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See detailPhotometric variability of southern CP stars
Manfroid, Jean ULg; Mathys, G.

in Astronomy and Astrophysics. Supplement Series (1986), 64

The photometric behavior of eight southern CP stars with relatively large amplitudes of variation is analyzed. Periods of variation and parameters of the light curves are obtained by least-squares fitting ... [more ▼]

The photometric behavior of eight southern CP stars with relatively large amplitudes of variation is analyzed. Periods of variation and parameters of the light curves are obtained by least-squares fitting. A wide variety is found in the periods and in the shapes of the light curves, confirming the lack of correlation between these parameters and the amplitudes. [less ▲]

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See detailPhotometric variability of some early-type stars
Mathys, G.; Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1986), 63

Photometric observations of 12 variable early type stars are presented. The properties of individual stars are discussed, and an attempt is made to interpret their variability. The information presented ... [more ▼]

Photometric observations of 12 variable early type stars are presented. The properties of individual stars are discussed, and an attempt is made to interpret their variability. The information presented on the stars includes the HD number and other identification, the observing runs, the periodicity of the variations, an error estimate, and a tentative classification of each star. [less ▲]

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See detailPhotometric variations of the irregular variable V348 SGR
Heck, A.; Houziaux, Léo ULg; Manfroid, Jean ULg et al

in Astronomy and Astrophysics. Supplement Series (1985), 61

The authors report visual estimates and photometric observations in various wavelength ranges of the irregular variable V348 Sgr. They cover dramatic drops of brightness (from V â 12.5 to â 18) which ... [more ▼]

The authors report visual estimates and photometric observations in various wavelength ranges of the irregular variable V348 Sgr. They cover dramatic drops of brightness (from V â 12.5 to â 18) which occurred in 1972, 1973 and 1981 with a time scale much shorter than the characteristic time mentioned by previous observers. These deep minima are, to our knowledge, the best followed up to now. The maximum brightness of the object seems also to correspond to V â 12 and not 10.5 as reported earlier. The minima reach V â 18, but this might represent the nebular contribution while the star itself might even go fainter. The main conclusions of this compilation are probably that the characteristic times given by Herbig (1958) from appearances on Harvard plates are most likely incorrect and that it is impossible to give one at all. The field of V348 Sgr has also been observed in the uvby system and a sequence is provided in this paper. [less ▲]

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See detailOn the shape of the UVBY lightcurves of CP stars
Mathys, G.; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1985), 60

The authors present the lightcurves in the Strömgren system of 56 CP stars. The observational data have been fitted by a sine wave and its first harmonic. The least-square parameters are tabulated and it ... [more ▼]

The authors present the lightcurves in the Strömgren system of 56 CP stars. The observational data have been fitted by a sine wave and its first harmonic. The least-square parameters are tabulated and it is shown that such a fit describes very well the CP variations in most cases, the only exceptions being due to observational uncertainties. [less ▲]

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See detailThe eclipsing variable HR 2800
Sterken, C.; Hensberge, H.; Vander Linden, D. et al

in Astronomy and Astrophysics. Supplement Series (1985), 60

The eclipsing variable star HR 2800 (HD 57593) is characterized on the basis of uvby photoelectric photometry and 20-A/mm coude spectrograph plates obtained at ESO and at SAOO during the period 1975-1983 ... [more ▼]

The eclipsing variable star HR 2800 (HD 57593) is characterized on the basis of uvby photoelectric photometry and 20-A/mm coude spectrograph plates obtained at ESO and at SAOO during the period 1975-1983. The data are presented graphically and used to estimate the ephemeris parameters of the eclipses, which have a depth in V of 0.25 mag, as time of minimum = JD 2,444,629.7797 + or - 0.010 and period = 24.6033 + or - 0.0003 days. HR 2800 is classified as a bright B-star Algol-type variable. [less ▲]

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See detailNew period determinations for variable CP stars
Manfroid, Jean ULg; Mathys, G.

in Astronomy and Astrophysics. Supplement Series (1985), 59

Periods, or improved determinations of periods, are presented for 29 CP stars observed at La Silla in 1977-1982. The PHOT2 program's algorithm makes possible the bringing together of different observing ... [more ▼]

Periods, or improved determinations of periods, are presented for 29 CP stars observed at La Silla in 1977-1982. The PHOT2 program's algorithm makes possible the bringing together of different observing runs, through an improved reduction of the data to a common standard system. It is noted that, in many instances, magnetic observations would be required for the resolution of ambiguities, especially in the presence of quasi-symmetric double waves. [less ▲]

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See detailOn period determination methods
Heck, A.; Manfroid, Jean ULg; Mersch, G.

in Astronomy and Astrophysics. Supplement Series (1985), 59

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965 ... [more ▼]

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965) are not equivalent to each other under general conditions. Instead, at best, all criteria may be expressed as the ratio of two quadratic forms. Numerical simulations have been conducted in order to compare the performance of Deeming's (1975) Fourier method, Burki et al.'s (1978) autocorrelation method, Lafler and Kinman's (1965) method, and the Renson (1978) and Stellingwerf (1978) methods. When applied to single-periodic phenomena, the tests indicate that none of the methods is clearly superior. [less ▲]

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See detailThe ultraviolet spectrum of the Be star HD 50138
Hutsemekers, Damien ULg

in Astronomy and Astrophysics. Supplement Series (1985), 60

The ultraviolet spectrum of the B8 Ve star HD 50138, recorded during the December 1978-January 1982 period with IUE, is analyzed. The spectrum is found to be crowded by absorption lines, mostly those of ... [more ▼]

The ultraviolet spectrum of the B8 Ve star HD 50138, recorded during the December 1978-January 1982 period with IUE, is analyzed. The spectrum is found to be crowded by absorption lines, mostly those of singly ionized iron peak elements. In addition there are broad lines essentially due to superionized species (Si IV, C IV) and a P Cygni profile for the Mg II doublet, similar to that seen in the star AB Aur. A few Fe II emission lines are also detected. The slowly expanding envelope surrounding HD 50138 appears to be decelerated outward with a decreasing ionization. The physical state of this envelope seems to suffer strong variations: a double structure was detected for some of the absorption lines in 1978-1979, and is interpreted as due to an outburst. A net increase of the excitation in 1980 is also observed and vanishes in 1982. In order to explain the unusual profiles of the Mg II lines, a possible fluorescence mechanism driven by Ly-beta is discussed. An accurate list of line identification is also provided. [less ▲]

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See detailCatalogue des périodes observées pour des étoiles Ap
Catalano, F. A.; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1984), 55

A table of all the periods proposed up to now for Ap stars is given with references. The main identifiers (HD, HR, ... numbers), the variable-star name, and the spectral type are listed for each star in ... [more ▼]

A table of all the periods proposed up to now for Ap stars is given with references. The main identifiers (HD, HR, ... numbers), the variable-star name, and the spectral type are listed for each star in the table. The nature of the periodic variability discovered (luminosity, equivalent widths of the lines, magnetic field, ...) is presented in a codified way. Notes are provided, mainly about duplicities. [less ▲]

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See detailPhotoelectric photometry of the peculiar emission-line star GG Carinae
Gosset, Eric ULg; Surdej, Jean ULg; Swings, J.-P.

in Astronomy and Astrophysics. Supplement Series (1984), 55

The first extensive sets of photoelectric observations of the peculiar emission-line star GG Carinae were obtained from 1977 to 1981, in both the standard UBV and Strömgren systems. A Fourier analysis of ... [more ▼]

The first extensive sets of photoelectric observations of the peculiar emission-line star GG Carinae were obtained from 1977 to 1981, in both the standard UBV and Strömgren systems. A Fourier analysis of 767 independent measurements leads to the determination of a period P = 31[SUP]d[/SUP].020 for the light variations. Different physical arguments based on the analysis of the present photoelectric - as well as previous photographic - data clearly indicate, however, that the true period is P = 62[SUP]d[/SUP].039. The resulting composite lightcurve displays two distinct maxima and minima with a total light amplitude Deltam â ¡ 0.5 mag. Additional interesting features are noticed in the mean lightcurve. Although it is not possible to classify GG Carinae among any known type of variable stars, the light variations of this object are similar to those observed for beta Lyrae-type systems. [less ▲]

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