The pioneering investigations in the field of the interstellar molecules, 1935-1942.

in Astrophysics & Space Science (1978), 55(1), 263-265

HD 45677 est-elle une étoile variable ?

in Astronomy and Astrophysics (1972), 17(1), 142-145

Whereas HD 45677 has faded by approximately one magnitude since 1969, the amplitude of variation in photographic magnitude between 1899 and 1969 has always been smaller than 0.3 mag.

Phénomènes de fluorescence dans les astres.

in Mémoires de la Societe Royale des Sciences de Liège (1971), 1

Possibility of Fluorescence Phenomena in the Ultraviolet Spectrum of Symbiotic Stars and Long Period Variables

in Houziaux, Léo; Butler, H. E. (Eds.) Ultraviolet Stellar Spectra and Related Ground-Based Observations : IAU symposium, held in Lunteren, The Netherlands, 24-27 June, 1969 (1970)

Consideration of the forbidden lines of iron in the states from Fe0 to Fe6+

in Mémoires de la Societe Royale des Sciences de Liège (1969), 17

The iron atom which has a fairly high cosmic abundance presents the great interest of appearing in a wide variety of stars and nebulae, at many stages of ionization, and of revealing forbidden transitions ... [more ▼]

The iron atom which has a fairly high cosmic abundance presents the great interest of appearing in a wide variety of stars and nebulae, at many stages of ionization, and of revealing forbidden transitions in emission in many of these ionization stages. The present paper discusses the following topics : (a) the case of the as yet undiscovered forbidden lines of neutral iron (Fe0) ; (b) some recently acquired astronomical information on the forbidden lines of the stages Fe+ to Fe6+ ; (c) general considerations on the important information revealed by these forbidden lines of iron on the physical structure and excitation mechanisms which are present in the emission line stars of early and late types. For lack of time we give only a very summarized version of our paper ; a complete text will appear later. [less ▲]

Free radicals in astrophysics.

in Mémoires de la Societe Royale des Sciences de Liège (1969), XVIII(3), 7-26

Final Session, 31 August 1967

in Transactions of the International Astronomical Union. Series B, Proceedings of the general assembly (1968), 13

Examples of astronomical needs for atomic spectra.

in Bashkin, Stanley (Ed.) Beam-Foil Spectroscopy; Volume 1. Proceedings of the conference held at the University of Arizona, USA, November 20-22, 1967 (1968)

The emission lines in the ultraviolet region 3140-3500A of CH Cygni, and related problems

in Astrophysical Letters & Communications (1967), 1

The M6 semi-regular variable CH Cygni had an outburst in June 1967. The emission lines of the ultraviolet region λ< 3500 Å are described. General considerations on the importance of this region are ... [more ▼]

The M6 semi-regular variable CH Cygni had an outburst in June 1967. The emission lines of the ultraviolet region λ< 3500 Å are described. General considerations on the importance of this region are outlined. [less ▲]

Spectrographic observations of Comet Ikeya-Seki (1965f).

in Astrophysical Journal (1965), 142