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See detailPhotometric observations of 1978CA and 1978DA
Surdej, Jean ULg; Surdej, Anna ULg

in The Messenger (1978), 13

UBV photometric observations of the earth-crossing asteroid 1978 CA and the Mars-crosser 1978 DA are reported. Light curves are plotted which indicate that 1978 CA has a rotation period of approximately 3 ... [more ▼]

UBV photometric observations of the earth-crossing asteroid 1978 CA and the Mars-crosser 1978 DA are reported. Light curves are plotted which indicate that 1978 CA has a rotation period of approximately 3 hr 45 min and that 1978 DA rotates about its axis much more slowly than 1978 CA. The following color indices are determined: (B-V) of approximately 0.90 and (U-B) of about 0.48 for 1978 CA and (B-V) = 0.83 and (U-B) = 0.41 for 1978 DA. A model that may explain the observed smooth and nearly symmetric light curve of 1978 CA is briefly discussed. [less ▲]

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See detailPhotometric observations of HD 50169.
Heck, A.; Maitzen, H. M.; Renson, Pierre ULg

in Astronomy and Astrophysics (1977), 54

Abstract image available at: http://adsabs.harvard.edu/abs/1977A&A....54..635H

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See detailPhotometric Observations of WR78 = HD 151932
Magain, Pierre ULg; Vreux, Jean-Marie ULg; Manfroid, Jean ULg

in Information Bulletin on Variable Stars (1987), 3022

Not Available

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See detailA photometric study of southern Ap stars having right ascensions on the order of 12 h
Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1983), 51

From uvby measurements periods have been deduced for the Ap stars 25 Sex, HR 4327, β Hya, HD 112381, HR 4965, HR 5158, HR 5269, and HD 125630. The star HR 4109 (Sr?) remained constant during an interval ... [more ▼]

From uvby measurements periods have been deduced for the Ap stars 25 Sex, HR 4327, β Hya, HD 112381, HR 4965, HR 5158, HR 5269, and HD 125630. The star HR 4109 (Sr?) remained constant during an interval of 23 d; the period is perhaps very long, or if HR 4109 actually does not vary, possibly it is not an Ap star. The observed variation for l Cen (Mn) was too weak to deduce a period. The variation range of HD 112381 (SiCr) is nearly as small as that of l Cen. The v and y variations for HD 125630 (SiCrSr), which are double-waved and nearly opposite to one another, have ranges among the largest known for Ap stars; the c[SUB]1[/SUB] range is also exceptionally large. For some Ap stars the variation curves show a dip of short duration in the four colours, and for a few stars a second one appears at a phase-interval of P/2. The nature of this phenomenon is discussed. [less ▲]

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See detailA photometric study of the bright cloud B in Sagittarius. VII - 1165 new variable stars and 65 diffuse objects
Terzan, A.; Gosset, Eric ULg

in Astronomy and Astrophysics. Supplement Series (1991), 90

A field in the Sagittarian bright cloud in the direction of the Galactic center is investigated by means of the B, V, and R Schmidt plates at the ESO, and 1165 variable stars are reported. The position, R ... [more ▼]

A field in the Sagittarian bright cloud in the direction of the Galactic center is investigated by means of the B, V, and R Schmidt plates at the ESO, and 1165 variable stars are reported. The position, R magnitudes, epochs, and amplitudes of variation are given for each star, and the surface density per square degree of variable stars increases from 1.7 to 65. The number of variables in the present field is similar to that for field A, and variables of type L and/or M are more densely numerous toward the center of the Galaxy than at other locations. Of the objects listed, 65 are given with potential classifications based on morphological data from the B and R Schmidt plates. The preliminary observations suggest a success rate of 42 percent on the precise prediction of the object types. [less ▲]

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See detailA photometric study of the Carina nebula region around WR 22
Kumar, Brajesh ULg; Manfroid, Jean ULg; Gosset, Eric ULg et al

in Bulletin de la Societe Royale des Sciences de Liege (2011), 80

We performed the first photometric observations of a field situated around WR 22 in the Carina nebula region. We present and discuss the preliminary results of the study.

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See detailA Photometric Study of the Hot Exoplanet WASP-19b
Lendl, M.; Gillon, Michaël ULg; Queloz, D. et al

in Astronomy and Astrophysics (2013), 552

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the ... [more ▼]

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the planet mass (with radial velocity data). For the study of planetary atmospheres, it is essential to obtain transit and occultation measurements at multiple wavelengths. Aims: We aim to characterize the transiting hot Jupiter WASP-19b by deriving accurate and precise planetary parameters from a dedicated observing campaign of transits and occultations. Methods: We have obtained a total of 14 transit lightcurves in the r'-Gunn, I-Cousins, z'-Gunn, and I + z' filters and 10 occultation lightcurves in z'-Gunn using EulerCam on the Euler-Swiss telescope and TRAPPIST. We also obtained one lightcurve through the narrow-band NB1190 filter of HAWK-I on the VLT measuring an occultation at 1.19 μm. We performed a global MCMC analysis of all new data, together with some archive data in order to refine the planetary parameters and to measure the occultation depths in z'-band and at 1.19 μm. Results: We measure a planetary radius of Rp = 1.376 ± 0.046 RJ, a planetary mass of Mp = 1.165 ± 0.068 MJ, and find a very low eccentricity of e = 0.0077-0.0032+0.0068, compatible with a circular orbit. We have detected the z'-band occultation at 3σ significance and measure it to be δFocc,z' = 352 ± 116 ppm, more than a factor of 2 smaller than previously published. The occultation at 1.19 μm is only marginally constrained at δFocc,NB1190 = 1711-726+745 ppm. Conclusions: We show that the detection of occultations in the visible range is within reach, even for 1 m class telescopes if a considerable number of individual events are observed. Our results suggest an oxygen-dominated atmosphere of WASP-19b, making the planet an interesting test case for oxygen-rich planets without temperature inversion. [less ▲]

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See detailPhotometric study of the lensed quasar HE0435-1223
Ricci, Davide ULg

Scientific conference (2010, February 11)

We present the preliminary results of a systematic multi-filter photometric observations of HE0435, carried with the Danish 1.54m telescope at the La Silla Observatory. We performed 2 seasons of ... [more ▼]

We present the preliminary results of a systematic multi-filter photometric observations of HE0435, carried with the Danish 1.54m telescope at the La Silla Observatory. We performed 2 seasons of monitoring in VRI spectral bands and we are reducing the data using an integrated C++ software developed in our team. [less ▲]

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See detailPhotometric variability of barium stars
Jorissen, A.; Manfroid, Jean ULg; Sterken, C.

in Astronomy and Astrophysics (1992), 253

Results are presented on uvby observations for up to 4 years of 19 southern barium stars. During the observation period, only two of the stars, HD 121447 and HD 46407, showed significant light variations ... [more ▼]

Results are presented on uvby observations for up to 4 years of 19 southern barium stars. During the observation period, only two of the stars, HD 121447 and HD 46407, showed significant light variations. These variables are the stars among the sample with the shortest orbital periods. In the case of HD 46407, evidence for eclipses was also found. It is noted that the evidence of varying phase shifts between the photometric eclipse and the spectroscopic ephemeris based on McClure and Woodsworth's (1990) orbital parameters makes it unlikely that the eclipsed light arises directly from the stellar companion of the barium star. It is also suggested that the flickering displayed by the reddest barium stars is a generic property of all red stars, because it was also observed for the comparison stars HD 204139 and HD 90677. [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 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 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 variations and period of the spectrum variable HR 3413.
Renson, Pierre ULg; Heck, A.; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 31

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1978A&AS...31..199R

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See detailPhotometric variations in Ap stars observable at La Silla in November and December
Renson, Pierre ULg; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1981), 44

Photometric observations of 13 Ap stars made at the European Southern Observatory at La Silla during November 1977 and December 1978 are reported. Observations were made in the uvby with the four-channel ... [more ▼]

Photometric observations of 13 Ap stars made at the European Southern Observatory at La Silla during November 1977 and December 1978 are reported. Observations were made in the uvby with the four-channel photometer at the 40-cm telescope in November, and with the one-channel photometer at the 50-cm telescope in December. Light variations with periods from 0.724 to 4.64 days are obtained for 11 of the stars, including the Hg-Mn star HR 2202, which was believed not to vary. Extremely small variations are observed in Upsilon 4 Eri, with a possible period of 0.51 days, although the two Mn components are likely to vary independently. HR 1800 was not observed to vary over two-week observation period. The stars 20 Eri, HR 1194, Alpha Dor, 11 Ori and HD 36916 are also noted to exhibit relatively large variations for Ap stars. [less ▲]

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See detailPhotometric variations of 46 Eridani and 210 G. Eridani
Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics (1989), 223

The photometric behavior in the uvby system of the Ap star 46 Eri is analyzed on the basis of new data. The revised period is P = 3.798777 + or - 0.000015 d. Knowledge of the accurate light-curve of 46 ... [more ▼]

The photometric behavior in the uvby system of the Ap star 46 Eri is analyzed on the basis of new data. The revised period is P = 3.798777 + or - 0.000015 d. Knowledge of the accurate light-curve of 46 Eri makes it possible to refine data on the multiperiodic B5III variable star 210 G. Eri, which was used as a comparison for 46 Eri. Four periods, all of the order of four days, are found with P(1) = 3.9215 d standing out clearly. This value is very large compared to those of other mid-B variables. [less ▲]

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See detailPhotometric variations of Ap stars
Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics (1994), 281

The photometric variations of seven Ap stars have been analyzed from observations mainly obtained in the framework of the Long-Term Photometry of Variables project at European Southern Observatory (ESO ... [more ▼]

The photometric variations of seven Ap stars have been analyzed from observations mainly obtained in the framework of the Long-Term Photometry of Variables project at European Southern Observatory (ESO). New values for the periods and detailed light curves in the uvby system are provided. Alpha Scl is shown to display anomalous variations that set it apart from the other stars. [less ▲]

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See detailPhotometric variations of HD 25267
Manfroid, Jean ULg; Mathys, G.; Heck, A.

in Astronomy and Astrophysics (1985), 144

Two periodicities are found in the photometric variations of HD 25267. One of the periods (1.2 d) seems to be the same as the magnetic period and is thus attributed to a CP component. The origin of the ... [more ▼]

Two periodicities are found in the photometric variations of HD 25267. One of the periods (1.2 d) seems to be the same as the magnetic period and is thus attributed to a CP component. The origin of the variations with the second period (3.8 d) remains uncertain. [less ▲]

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See detailPhotometric variations of some Ap stars.
Renson, Pierre ULg; Manfroid, Jean ULg; Heck, A.

in Astronomy and Astrophysics. Supplement Series (1976), 23

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1976A&AS...23..413R

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See detailPhotometric variations of southern Ap stars.
Renson, Pierre ULg; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 34

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1978A&AS...34..445R

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See detailThe photometric variations of the Ap star HD34631
Manfroid, Jean ULg; Renson, Pierre ULg; Catalano, F. A. et al

in Astronomy and Astrophysics. Supplement Series (1991), 90

The photometric behavior in the uvby system of the Ap star HD34631 has been reanalyzed on the basis of data collected over a time span of 16 years. A more accurate value of the period is deduced: P = 2 ... [more ▼]

The photometric behavior in the uvby system of the Ap star HD34631 has been reanalyzed on the basis of data collected over a time span of 16 years. A more accurate value of the period is deduced: P = 2.20269 +/-0.00004d. The lightcurves show a double-wave shape. The variations are smallest in the v band. [less ▲]

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