Le spectre de la nébuleuse planétaire IC 3568

in Publications de l'Observatoire de Haute-Provence (1958), 4(31), 161-162

Observations spectroscopiques de la comète Arend-Rolland (1956 h).

in Annales d'astrophysique (1957), 20

Aux distances héliocentriques inférieures a 0,6 U. A., le spectre d'émission de la comète 1956h montre un doublet D anormalement intense. L'intensité du continuum est toujours élevée. On a obtenu une plus ... [more ▼]

Aux distances héliocentriques inférieures a 0,6 U. A., le spectre d'émission de la comète 1956h montre un doublet D anormalement intense. L'intensité du continuum est toujours élevée. On a obtenu une plus grande precision pour les longueurs d'onde des émissions jaunes-rouges ; celles-ci appartiennent toutes aux transitions (o, v2', o) → (o, o, o) de NH2 pour 5 ≤ v2' ≤ 10, les branches Q étant les mieux marquées. [less ▲]

Considérations sur les identifications dans les spectres cométaires

in Annales d'astrophysique (1957), 20

Une comparaison minutieuse des spectres comitaires et des spectres de nombreux composes de l'hydrogène, du carbone et de l'oxygène n'a révélé aucune importante nouvelle identification cométaire. La ... [more ▼]

Une comparaison minutieuse des spectres comitaires et des spectres de nombreux composes de l'hydrogène, du carbone et de l'oxygène n'a révélé aucune importante nouvelle identification cométaire. La difficulté principale est due à l'imprécision des longueurs d'onde cométaires. [less ▲]

Comète Arend-Roland (1956 h)

in Astronomie (L') (1957), 71

Les équilibres de dissociation moléculaire

in Astronomie (L') (1957), 71

Astrophysique : le spectre de la comète 1957c (Encke)

in Publications de l'Observatoire de Haute-Provence (1957), 4(7), 3

The spectra of the comets

in Vistas in Astronomy (1956), 2

The Introduction deals with the essential information on the nucleus, the coma, and the tail of comets, which may be obtained by direct photography, photometry, and polarization techniques; the need for ... [more ▼]

The Introduction deals with the essential information on the nucleus, the coma, and the tail of comets, which may be obtained by direct photography, photometry, and polarization techniques; the need for "monochromatic" observations is emphasized. It is followed by a description of the emission spectrum of the coma (from the OH emission near 3100 to the red CN band near 8100) and by that of the spectrum of the tail in the ultraviolet and photographic regions, with emphasis on the recently discovered bands. The complex profile of the emission bands is shown to be due to a resonance fluorescence excitation, account being taken of the absorption lines of the exciting solar radiation; other possible excitation mechanisms are briefly mentioned. The probable assignment of the 4050 group to the tricarbon molecule and its consequences are discussed. The paper ends with physical considerations on the still unidentified emissions, on desirable physical investigations, on the parent molecules, and the production and evolution of cometary atmospheres, and on the densities and the extent of molecules in the cometary head. [less ▲]

L'Astrophysique moléculaire

in Astronomie (L') (1956), 70

[Préface]

in Jacquemyns, G. (Ed.) Energie nucléaire et bombe atomique : un sondage d'opinion publique (1954)

Spectra of the late N-type stars in the ultra-violet, violet and blue-green regions

in Monthly Notices of the Royal Astronomical Society (1953), 113

Spectrograms of several late N-type stars have been obtained covering the far violet spectral region from λ 4100 to λ 3900. One plate of Y CVn extends the observations into the ultra-violet, radiation ... [more ▼]

Spectrograms of several late N-type stars have been obtained covering the far violet spectral region from λ 4100 to λ 3900. One plate of Y CVn extends the observations into the ultra-violet, radiation being detectable below λ 3500. A list of the wave-lengths of the absorption features and the emission-like spaces between them is given for the interval λ 3400 to λ 4100. The ultra-violet spectrum of Y CVn is dominated by a series of newly discovered broad absorption bands centred about λλ 3790, 3700, 3595 and 3480, for which no identification is found. The λ 4100-λ 3900 region of the several late N-type stars exhibits the series of absorption bands previously found for Y CVn, these bands being separated by comparatively sharp regions of background radiation. The λ 4050 group of bands as found in the laboratory and in cometary spectra, currently provisionally ascribed to C3, is discussed. Comparison of the stellar absorptions with the laboratory and cometary bands is made. While the stellar bands cannot be identified with the others for certain, the previous tentative identification is believed strengthened. The unidentified blue-green bands characteristic of late N-type spectra, as photographed with moderately high resolution, are found to reveal no rotational structure. Hence the suggestion that they might arise from a diatomic hydride must be abandoned. It is noted that the spectrum of the irregular variable, U Hya, sometimes shows the blue-green bands and, when it does, the λ 4050 group and high opacity in the far violet, associated with late N-type spectra, are also present. When the blue-green bands are absent, the violet bands are also absent and the spectrum is of early N-type. Various considerations are believed to favour a polyatomic molecular origin for the blue-green bands ; as for the high opacity in the far violet, it is related to the formation of the molecules responsible for the λ 4050 absorption. [less ▲]