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See detailA photoelectric investigation of light variability in Ap stars
Hensberge, H.; Deridder, G.; Doom, C. et al

in Astronomy and Astrophysics. Supplement Series (1981), 46

A study of the light variability of a number of peculiar A stars, mainly in Stromgren colors u and v and in peculiarity index Delta-a, leads to the proposal of the following light variability periods: (1 ... [more ▼]

A study of the light variability of a number of peculiar A stars, mainly in Stromgren colors u and v and in peculiarity index Delta-a, leads to the proposal of the following light variability periods: (1) HD 5601, 1.11 days; (2) HD 19712, 2.19 days; (3) HD 30849, 15.86 days; (4) HD 38823, 8.64 days; (5) HD 53116, 11.98 or 18.10 days; (6) HD 56022, 0.92 days; and (7) HD 81009, 33.97 days. In addition, evidence is given for variability of HD 94660 on a time scale on the order of months or years, and it is shown that the rotation period proposed by Borra and Landstreet (1980) for HD 25267 is not supported by the light variations observed. The character of Delta-a variability is discussed. [less ▲]

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See detailPhotoelectric light curves of minor planets 599 Luisa and 128 Nemesis during the 1976 opposition
Debehogne, H.; Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1977), 30

Asteroids 599 Luisa and 128 Nemesis were observed photometrically at the European Southern Observatory during the 1976 opposition. The light curve of 599 Luisa shows two well-shaped minima and maxima ... [more ▼]

Asteroids 599 Luisa and 128 Nemesis were observed photometrically at the European Southern Observatory during the 1976 opposition. The light curve of 599 Luisa shows two well-shaped minima and maxima together with a short-time-scale feature. The synodic period of rotation found for 599 Luisa 9 hr 33 min 58 (+ or -46) sec, and the maximum amplitude of the light curve is 0.18 mag. Minor planet 128 Nemesis could only be observed during one night and appears to be a slowly rotating asteroid. [less ▲]

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See detailPhotoelectric lightcurves and rotation period of the minor planet 148 Gallia
Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1979), 37

Abstract image available at: http://esoads.eso.org/abs/1979A&AS...37..471S

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See detailPhotoelectric lightcurves and rotation period of the minor planet 201 Penelope
Surdej, Jean ULg; Louis, B.; Cramer, N. et al

in Astronomy and Astrophysics. Supplement Series (1983), 54

Results of photoelectric observations of the asteroid 201 Penelope carried out at the European Southern Observatory and Perth Observatory during the 1980 opposition of the asteroid between October 6 and ... [more ▼]

Results of photoelectric observations of the asteroid 201 Penelope carried out at the European Southern Observatory and Perth Observatory during the 1980 opposition of the asteroid between October 6 and November 7 are presented. Observations were made in the standard UBV and Geneva systems at ESO, and in V-prime at Perth. Examination of composite light curves shows the presence of two distinct maxima and two distinct minima, with a total amplitude of the V light curve of 0.52 magnitudes. A mean synodic rotation period of 3 h, 44 min, 51.6 + or - 7.4 sec is derived. Using a mean phase coefficient beta[SUB]V[/SUB] = 0.037 mag/deg, a primary V (1,0) maximum of 8.51 + or - 0.01 magnitudes is obtained. Color indices are measured as B-V = 0.70 + or - 0.01 and U-B = 0.23 + or - 0.02 magnitudes, and previously reported color variations (Surdej and Cramer, 1980) are attributed to a failure in the reduction procedure. [less ▲]

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See detailPhotoelectric lightcurves and rotation period of the minor planet 59 Elpis
Debehogne, H.; Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 33

Abstract image available at: http://esoads.eso.org/abs/1978A&AS...33....1D

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See detailPhotoelectric lightcurves of the minor planets 29 Amphitrite, 121 Hermione and 185 Eunike
Debehogne, H.; Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 32

Abstract image available at: http://esoads.eso.org/abs/1978A&AS...32..127D

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See detailPhotoelectric observations of two unusual asteroids - 1978 CA and 1978 DA
Schuster, H. E.; Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1979), 37

The two fast-moving asteroids 1978 CA and 1978 DA, discovered in February 1978 with the ESO Schmidt telescope at La Silla (Chile), were observed with a photoelectric photometer attached to the 1-m ESO ... [more ▼]

The two fast-moving asteroids 1978 CA and 1978 DA, discovered in February 1978 with the ESO Schmidt telescope at La Silla (Chile), were observed with a photoelectric photometer attached to the 1-m ESO telescope. The light curve of 1978 CA displays two fairly symmetric maxima and minima with a total amplitude of 0.8 mag in V. The synodic period of rotation found is 3 h 45 m and places 1978 CA as the third fastest rotator among all known solar objects. Concerning the minor planet 1978 DA, light variations covering one full cycle of rotation could not be monitored. Nevertheless, the rotation period exceeds 5 h, and the total amplitude is greater than 0.35 mag. [less ▲]

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See detailPhotoelectric photometry of 22 Kalliope during the 1985 opposition and determination of its pole orientation - The 'magnitude-aspect' relations revisited
Surdej, Jean ULg; Pospieszalska-Surdej, Anna ULg; Michalowski, T. et al

in Astronomy and Astrophysics (1986), 170

Abstract image available at: http://esoads.eso.org/abs/1986A&A...170..167S

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See detailPhotoelectric photometry of Comet Halley from Mt Tamborine observatory
Page, A. A.; Nielsen, G. E.; Jones, K. L. et al

in Vistas in Astronomy (1988), 31

Post-perihelion photoelectric observations of comet Halley carried out during several weeks are reported. The measurements confirm the existence of large-amplitude night-to-night changes.

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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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See detailPhotoelectric scans of comet Halley.
Sterken, C.; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in Diversity and Similarity of Comets (1987, September 01)

The authors compare radial photometric scans of comet Halley obtained in April 1986 at the European Southern Observatory, La Silla, Chile, with theoretical profiles derived from Haser's model.

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See detailA Photoelectron Spectroscopic Investigation of Vinyl Fluoride (C2H3F). The HeI, Threshold and CIS Photoelectron Spectroscopy.
Locht, Robert ULg; Leyh, Bernard ULg; Dehareng, Dominique ULg et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2010), 43(1), 01510215

The threshold photoelectron spectrum (TPES) and the constant ion state (CIS) spectra of the individual ionic states of C2H3F have been recorded using synchrotron radiation. For comparison a well resolved ... [more ▼]

The threshold photoelectron spectrum (TPES) and the constant ion state (CIS) spectra of the individual ionic states of C2H3F have been recorded using synchrotron radiation. For comparison a well resolved HeI photoelectron spectrum (HeI-PES) has also been measured and analyzed in detail. The TPES has been measured between 9.5 eV and 35 eV photon energy. Numerous vibrational structures, reported for the first time, observed in the ground state and the six excited states of the cation are analyzed. Quantum chemical calculations have been performed and provide strong support to the assignments. State selected CIS spectra highlighted the major importance of autoionization for the production of almost all ionized states of C2H3F observed in this work. [less ▲]

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See detailPhotoelectron Spectroscopy of Vinyl Bromide and Intramolecular Dynamics of the ionic B state.
Hoxha, A.; Locht, Robert ULg; Leyh, Bernard ULg et al

in Chemical Physics (2000), 256

In this paper we report the He(I) photoelectron spectrum (PES) and the threshold photoelectron spectrum (TPES) of C2H3Br. The fine structure in the first two ionic states in the He(I) spectrum is assigned ... [more ▼]

In this paper we report the He(I) photoelectron spectrum (PES) and the threshold photoelectron spectrum (TPES) of C2H3Br. The fine structure in the first two ionic states in the He(I) spectrum is assigned to progressions belonging partially to previously unobserved vibrational modes. The TPES has been measured between 9.0 and 25.0 eV, and the photon energy range of 9.8-12.0 eV has been investigated in more detail. Extensive calculations with the GAUSSIAN set of programs have been performed to help in the assignment of the observed features. Furthermore, a conical intersection between the A2A" and the B2A" states was found to take place along the C-Br stretching coordinate. Intramolecular dynamics of the B2A" state, initially prepared in the Franck-Condon region, was probed by the Fourier transform of the spectrum. The B2A" state is almost readily depleted, most probably due to a very effective internal cnversion through the conical intersection. [less ▲]

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See detailPhotoferrotrophy and Fe-cycling in a freshwater column
Llirós, M; Crowe, SA; García-Armisen, T et al

Conference (2013)

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See detailPhotoferrotrophy and Fe-cycling in a freshwater column
Llirós, M; Crowe, SA; García-Armisen, T et al

Poster (2013)

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See detailLa photogrammétrie: un procédé pour mesurer les arbres à troncs irréguliers
Bauwens, Sébastien ULg; Fayolle, Adeline ULg; Nzenga, Alide Kidimbu et al

Conference (2013, April)

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See detailPhotogrammetry for forest inventory
Pierrot Deseilligny, Marc; Lisein, Jonathan ULg

Conference (2013, March 12)

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See detailLa photographie [en Wallonie]
Mélon, Marc-Emmanuel ULg

in Demoulin, Bruno (Ed.) Histoire culturelle de la Wallonie (2012)

A short history of photography in Wallonia

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