Evolution du spectre de la Nova Delphini 1967 dans le proche infrarouge en 1969

Spectra of Nova Del 1967 have been obtained in the photographic infrared during the period March to November 1969. The gradient in the region 1.3–1.7 µ^–1 has decreased from 3.06 in November 1968 to 2.57 in November 1969. The main spectral features occurring in the wavelength range 5800–9600 Å are described, while the profiles of some strong lines are displayed on Figures 2–6.

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Les observations ont été effectuées à l'Observatoire de Haute-Provence (CNRS).     

Analyse photometrique de l'eclipse de lune du 16 Septembre 1978

Sommaire La discussion de l'éclipse du 16.IX.1978 basée sur la comparaison des mesures photométriques de l'ombre avec la théorie basée sur l'atmosphère terrestre (pure). Les différences de la densité observée et de la densité calculée sont partiellement dues à l'absorption dans la couche d'ozone, mais le reste doit être attribué à l'absorption dans le milieu situé au-dessus de la couche d'ozone.

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The discussion of the eclipse 1978.IX.16 based on the comparison of the photometrical measurements of the shadow with the theory based on pure terrestrial atmosphere, is presented. The differences between the observed and computed density of the shadow are partly due to the absorption in the ozone layer, and the remainder can be attributed to the absorbing medium above the ozone layer.

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Décédé subitement le 2 décembre, 1979.     

Evolution du spectre de la Nova Delphini 1967 en 1971 et 1972

Continued spectroscopic observations of Nova Del 67 during 1971 and 1972 show a general decrease of the nebular and coronal emission with respect to the local continuum. The continuous spectrum exhibits a strong Balmer emission (figure 1). Equivalent widths of Hi, Hei, Heii, Oi, [Oi], Oii, [Oii], Oiii, [Oiii], Niii, [Sii], [Aiii], [Neiii], [Nev], [Fevi], [Fevii], [Fex], [Fexi], [Fexiv], [Nixvi], [Nixv] are listed in tables 1 and 2.Figures 5 to 10 show several line profiles, which can be interpreted in terms of a model proposed by Hutchings (1972). Kinematical properties of the nova envelope do not seem to have changed in the 1968–1972 time interval. However, a study of the [Oiii] (4959 Å) line indicates that the physical conditions in the polar blobs in 1972 (T _e=10 660 K,N _e=5,5×10⁵ cm^–3) are different from those prevailing in equatorial rings (T _e=9×100 K,N _e=7×10⁵ cm^–3).

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Le matérial d'observation utilisé pour cette étude a été obtenu à l'aide de téléscopes de 120 cm, 152 cm et 193 cm de l'Observatoire de Haute-Provence (CNRS).     

Sur une reduction des equations du mouvement du probleme des 3 corps

Résumé Dans cet article nous étudions, dans un premier temps, la réduction des équations du mouvement du problème plan des 3 corps en introduisant le groupe des similitudes planes dans la 1-forme de Poincaré. Ceci permet de dégager le cas des trajectoires de moment cinétique nul et d'énergie nulle. Nous envisageons ensuite la réduction du problème dans l'espace en établissant un lien remarquable avec le problème plan.

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In this article we first of all study the reduction of the equations of movement of the planar three body problem through the introduction of the group of similitude in Poincare's 1-form. This brings out the case of trajectories with zero angular momentum and zero energy. We then consider the reduction of the problem in space by establishing a remarkable link with the planar problem.

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Proceedings of the Sixth Conference on Mathematical methods in Celestial Mechanics held at Oberwolfach (West Germany) from 14 to 19 August, 1978.     

Analyse de l'Ombre extérieure pendant les Éclipses de lune

Sommaire L'analyse photométrique de l'ombre extérieure pendant 20 éclipses de 1921 à 1968 sur la base d'un matériau homogène d'observations révèle l'existence de la luminescence du sol lunaire excitée par les radiations corpusculaires solaires. L'influence de la haute atmosphère terrestre vers 25 km d'altitude se manifeste au bord de l'ombre.

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Photometric analysis of the peripheric umbra during 20 eclipses between 1921 and 1968 based upon the homogeneous observational material reveals the existence of the lunar luminescence excited by solar corpuscular radiations. The influence of the terrestrial upper atmosphere at about 25 km height is detectable on the border of the umbra.

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En congé de l'Institut Astronomique de l'Académie des Sciences, Prague.     

Analyse photométrique de la pénombre pendant les Éclipses de lune

Sommaire L'analyse photométrique de la pénombre pendant 21 éclipses de 1921 à 1968 sur la base d'un matériau homogène d'observations revèle des anomalies explicables par la luminescence du sol lunaire excitée par les radiations UV-X solaires dont les sources se situent dans la basse couronne et au-dessus des plages K-3. L'influence de la haute atmosphère terrestre se manifeste au bord de l'ombre.

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Photometric analysis of the penumbra during 21 eclipses between 1921 and 1968 based upon the homogeneous observational material reveals some anomalies which may be explained by the lunar luminescence excited by UV-X solar radiations whose sources are located in the low corona and above the K-3 plages. The influence of the terrestrial upper atmosphere is detectable on the border of the umbra.

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Ex-astronome à l'Observatoire de Bordeaux.

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En congé de l'Institut Astronomique de l'Académie des Sciences, Prague.     

Methode rapide de calcul d'une trajectoire de petite planete par l'approximation de tchebycheff,et son ajustement aux observations

It is shown that the application of the Chebyshev theory of approximation to the calculation of the orbit of a minor planet allows the production of a compact ephemeris, based on data gathered over only a short time, which is both accurate, and simple and rapid to produce. Adjustment of numerical data to fit observational results is readily performed. Using Clenshaw's algorithm, an ephemeris may even be worked out on a pocket calculator. Further applications of Chebyshev polynomials to the calculation of parameters usually obtainable only by interpolation of classical ephemerides, and to the calculation of minor planetary orbits from observations of short duration by an orbiting telescope are discussed.

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Presented at the Symposium Star Catalogues, Positional Astronomy and Celestial Mechanics, held in honor of Paul Herget at the U.S. Naval Observatory, Washington, November 30, 1978.     

Theorie litterale du neuvieme satellite de Saturne,Phoebe

We study a theory for the ninth satellite of Saturn, Phoebe, based on the literal solution we have obtained in the main problem of the lunar theory.These series were computed by solving, by successive approximations, the Lagrange's equations expressed in variables, functions of the elliptic elements.We may consider the case of Phoebe simpler than a lunar case because we seek less precision (1/10 geocentric) than in the Lunar case, although the eccentricity of Phoebe is stronger.Main problem: our series are computed to the complete seventh order and a great part of the perturbations of the eighth and ninth order, where we have attributed to the small lunar parameters the order 1 tom ₀=n/n ₀,e ₀,e, sin (i ₀/2), the order 2 to ₀=(a ₀/a)((M ₁–)/(M ₁+M)) and the order 4 toµ ₀(a ₀/a)M ₁ M/M ₁ ² –M ².In the case of Phoebe,µ ₀ equal zero and ±₀ is the ratioa ₀/a.We study the further development of these series by using, instead of parameterm ₀, the quantity m ₀=n/n ₀–m ₁ wherem ₁ is an approached value ofm ₀, in order to accelerate the convergence of the series with respect tom ₀.Comparison with a numerical integration we are adjusting a numerical integration to the observations. We have already more than 100 observations, for the period 1900–1957.At first, we compare the series of the main problem to a numerical integration of the Keplerian problem.

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Proceedings of the Conference on Analytical Methods and Ephemerides: Theory and Observations of the Moon and Planets. Facultés universitaires Notre Dame de la Paix. Namur, Belgium, 28–31 July, 1980.     

La transformation de Lyapunov de l'equation de Hill et son interpretation dynamique

Résumé La transformation de Lyapunov transforme une équation de Hill en une autre qui occupe la même place dans la classification de Yakubovich.Soit (C) une solution périodique d'un système conservatif à deux degrés de liberté. D'après le principe de moindre action de Maupertuis (C) est l'image d'une géodésique ().Nous montrons que les équations aux variations au voisinage de (C) et de () sont réductibles à deux équations de Hill qui se correspondent par une transformation de Lyapunov.

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The Lyapunov transformation of Hill's equation and his dynamic interpretation

The Lyapunov transformation carries Hill's equationÿ+F(t)y=0,F(t+T)=F(t) into another one which belongs to the same class in Yakubovich's classification.Let (C) be a closed trajectory of a Lagrangian conservative system with two degrees of freedom. By the Principle of Least action, we know that (C) is the image of a geodesic () of a certain two-dimensional surface ().We show that the two Hill equations associated with (C) and () are related by a certain Lyapunov transformation.

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Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.     

Trajectoires rectilignes du problème des 3 corps,lorsque la constante des forces vives est nulle

This problem is reducible to the integration of the EulerChazy's differential equation. We give a new simplified version of the equation, and we interpret in the corresponding diagram the study of two extreme degenerate cases.

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Presenté à la Conference du Mécanique Céleste, Oberwolfach, Germany, août 27–septembre 2, 1972.     

Etude d'une solution de la theorie litterale du probleme principal du mouvement de la Lune convergence formelle

Résumé Dans l'exposé qui va suivre, nous rappelons d'abord le système d'équations et le mode d'intégration que nous avons utilisés pour construire une théorie littérale du problème principal du mouvement de la Lune. En particulier, puisque, du fait de la présence des petits diviseurs, nous avons à effectuer plusieurs itérations à un ordre donné, pour obtenir tous les termes correspondant à cet ordre, nous allons étudier un système d'équations réduit qui se substitue au système complet, après la première intégration à un ordre donné. Ce système permet d'alléger au maximum les calculs.Nous étudions alors la convergence formelle de la solution littérale obtenue. Cette démonstration est faite par récurrence. Au cours de celle-ci, nous avons utilisé les propriétés du système d'équations réduit (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, et C12), système dont nous donnons dans les tableaux I à IV, les coefficients et les arguments. L'étude de l'ordre des termes engendrés par ce système nous permet de conclure que, si l'on connaît tous les termes d'ordren–1 alors on peut déterminer tous les termes d'ordren.Enfin, nous indiquons les résultats que nous avons actuellement obtenus par cette méthode.

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In this paper, we first recall the set of equations and the method of integration for a literal solution of the main problem of the lunar theory. As, owing to small divisors, we have to make many iterations at a given order to obtain all the corresponding terms, we study a restricted set of equations which replaces the complete system after the first integration at a given order. This set helps to make the calculations less bulky.Then we study the formal convergence of the literal solution thus obtained. The demonstration uses a recurrent process in which we made use of the properties of the restricted system of equations (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 and C12), the coefficients and arguments of which are given in Tables I to IV.The study of the order of magnitude of the terms formed by this system leads to the conclusion that if then–1 order terms are known, all then-order terms may be determined.In the end, we show the results obtained so far with this method.

     

Les raies du triplet de l'helium de la Nova Delphini 1967

The aim of this paper has been to study the neutral helium triplet emission lines identified in the spectrum of the envelope of Nova Delphini. By comparing the observed flux of the neutral helium lines with that calculated theoretically by Robbins, we find that the optical thickness in the center of the line 3889 is of the order of 21.50 for summer 1969. The optical thickness obtained by this method is here denoted _tran(3889).On the other hand, we obtain the number of neutral helium atoms in the 2³S state [N(2³S)] by considering the equilibrium between the mechanisms that populate and depopulate this state. We then find that the depopulation by photoionization due to the radiation of Ly (Hi), transitions to the 2¹S, 2¹p and 2³p states by electron collision, photoionization due to the continuum radiation of the central star, are 82.70%, 13.20%, 2.40%, 0.90% and 0.80% respectively. We find that the mechanism of the photoionization by Ly is the dominant mechanism of depopulation of 2³S state. We calculated ( 3889) of the order of 82.37, fromN(2³S), obtained in the preceding paragraph. The optical thickness obtained by this method is here denoted _bal(3889).The difference between _tran(3889) and _bal(3889) is very large and it cannot be attributed to calculation errors. We have considered all the mechanisms that can depopulate the 2³S state, so we then conclude that the difference between _tran(3889) and _bal(3889) is due to the heterogeneity of the envelope of the Nova, already found by us in our previous study of the profiles of the permitted and forbidden lines. Finally, we find from this study a filling factor of the order of 0.30.     

400 Jahre Mathematik und Astronomie an der Universität Würzburg: Alma Julia Herbipolensis 1582–1982

Ohne Zusammenfassung

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400 years mathematics and astronomy at the Wurzburg University: Alma Julia herbipolensis 1582–1982

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s. O. Volk, Mathematik, Astronomie und Physik in der Vergangenheit der Universität Würzburg, Festschrift 1982.

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Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.     

Sur les petits diviseurs I. (complement). Les series de V. Zeipel [on the small divisors. I. (complement). the V. Zeipel's series]

Résumé On démontre ici la convergence des séries de v. Zeipel excluant les termes à courte période de la fonction perturbatrice.

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The convergence of the v. Zeipel's series excluding the short periodic terms of the perturbation function has been established.

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Cette remarque est due à M.N.N. Vassiliéff, à qui l'auteur expresse ici sa reconnaissance.     

Evolution du spectre de HR Del de 1973 À 1979

Résumé De 1973 à 1979, on observe une diminution de l'intensité des raies d'émission et du continuum de HR Del au cours du temps.En 1978, on note la disparition des raies de haute excitation.La répartition énergétique spectrale dans le continu reste sensiblement la même dans l'intervalle 4000–5000 Å. Le fort excès ultraviolet trouvé de 3600 à 3250 Å est confirmé par les observations dans l'ultraviolet lointain effectuées à l'aide du satellite IUE.Nos observations montrent un important changement dans la structure des raies 4959 et 5007 Å de [Oiii] entre 1973 et 1976, les composantes polaires devenant plus faibles que les composantes équatoriales.

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From 1973 to 1979, the intensity of emission lines and continuum of HR Del has steadily diminished.High excitation lines have disappeared in 1978.The spectral energy repartition in the continuum remains the same in the spectral range 4000–5000 Å. The strong ultraviolet excess found in the spectral range 3600–3250 Å is confirmed by IUE satellite observations in the ultraviolet.Our observations show an important change in the structure of the [Oiii] lines 4959 and 5007 Å between 1973 and 1976, the polar components becoming weaker than the equatorial ones.

     

Spectres de quelques étoiles Be entre 7000 et 9600 Å

Kodak IM plates have been used in order to extend to 9600 Å the observed wavelength range for 23 O, B, Be Bp and A stars. The spectra are shown in the plate. Several atmospheric absorption bands perturb the continuum and line spectrum. Between 1.45 and 1.20 ^-1, we have measured the parameter d logI /d(1/). The results appear in the table and indicate that Be stars do not exhibit anomalous reddening in this spectral region. On the other hand the above parameter is much more sensitive to the reddening than to the star's effective temperature.

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Le matériel d'observation utilisé pour le présent travail a été obtenu à l'observatoire de Haute-Provence. (CNRS)     

Theorie generale planetaire etendue au cas de la resonance et application au systeme des satellites galileens de Jupiter

We consider a system of planets defined by a given distribution of mean mean motions and masses: we represent the osculating elliptic elements of their heliocentric orbits by quasi-periodic functions of time, through a method adapted to the commensurability case; these functions are the sum of the general solution of a critical system, expressed in long-period terms, and of a particular solution. As in the B. Brown's method (applied to the galilean satellites), the critical system contains the secular terms, the longperiod terms (great inequalities), and the resonant terms; the particular solution consists of short-period terms only, whose amplitude is an explicit function of the solution of the critical system.If all the long-period terms in the critical system are harmonic of one fundamental term, we can perform a simple change of variables which transforms the critical system in an autonomous one, and thus we reduce the resolution to an eigenvalue problem. Applying that to the galilean satellites of Jupiter and neglecting the solar perturbations, we obtain a differential system with constant coefficients, whose linear part concerns all the variables (including the major-axes and the mean longitudes) and gives, as a first approximation, the great inequalities, the free oscillations and the libration; nevertheless this solution agrees already with known results, but should be improved by taking into account the non-linear parts and the solar terms in a new approximation.

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Proceedings of the Conference on Analytical Methods and Ephemerides: Theory and Observations of the Moon and Planets. Facultés universitaires Notre Dame de la Paix, Namur, Belgium, 28–31 July, 1980     

Theorie analytique programmee de la libration physique de la lune

Résumé La rotation de la Lune autour de son centre de gravité est traitée par une méthode analytique, en tenant compte de son mouvement orbital. On développe une théorie Hamiltonienne en utilisant les variables d'Andoyer et l'on démontre que les écarts, purement périodiques, à trois relations de résonances similaires aux lois de Cassini, sont les variables canoniques du problème. Le potentiel est exprimé dans ces nouvelles coordonnées et l'Hamiltonien est développé jusqu'au deuxième degré en les petites variables. Un système d'équations donne le vrai centre de libration qu'on trouve proche du centre défini par les lois de Cassini. Un second système, résolu par un processus d'iterations, donne les séries de la libration, analytiques par rapport aux constantes du potentiel de la Lune et trigonométriques en les arguments de Delaunay. La question de convergence est brièvement abordée, mais sans démonstration.

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The rotation of the Moon about its center of mass, taking into account the orbital motion, is treated analytically. A Hamiltonian theory is developed in terms of the Andoyer variables. The periodic parts of departures from three resonances, equivalent to Cassini's laws, are found to be the canonical variables of the problem. The potential is expressed as a function of these new coordinates and the whole Hamiltonian is developed to the second degree in these small variables. One system of equations gives the real center of libration which is found to be near the center defined by Cassini's laws. A second system solved by iterations, gives the libration as analytical series in the constants of the Moon's potential, and trigonometric series in Delaunay arguments. The question of convergence is briefly exposed without any demonstration.

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Ce travail a été soutenu par une bourse du Centre National d'Etudes Spatiales.     

Nova Delphini 1967. Observations du spectre nebulaire entre 5600 et 8800 Å en 1970

Five 230 Å/mm infrared spectra of Nova Delphini 1967 have been obtained from May to September 1970 on Kodak hypersensitized IN plates. Visual brightness has dropped by one magnitude between fall 1969 and fall 1970. The continuous spectrum remains strong and a mean value of 2.35 is found for the gradient in the region 6000–8000 Å, indicating a slight increase in temperature since 1969. Permitted lines ofHi,Oi, Hei, Feii are weakening, while intensities of forbidden transitions due [Nii], [Fevii], [Oi], [Oii], [Aiii], [Av], [Fevii], [Fex], [Fexi], [Fexi], [Nixv] are much more stable At the dispersion of our spectra, there is little evidence of activity in the nova shell during 1970. Temperature seems to be slightly increasing in the lower layers as well as in the external, low density regions.

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Les observations ont été effectuées à l'Observatoire de Haute-Provence (C.N.R.S.)     

Determination des demi-grands axes des satellites galileens de Jupiter

In non-resonant cases, a constant part coming from the perturbations can be easily separated from the observed mean mean motion, which can be called the perturbed part. An another part created by resonance must be separated from the observed mean motion in the case of the first three Galilean satellites. The determination of it gives better value of the semi-major axis.In this investigation, the analytical process is chosen to avoid a mixture of orders in successive expansions and integrations.The main terms entering in the computation of the libration are the great inequalities of the first three satellites. Each of them is introduced in the development by its eight components; while in Sampson's theory, only the great inequality of Satellite 2 is given by two components.The equations of motion used in this work are derived from Sagnier's theory.

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Proceedings of the Conference on Analytical Methods and Ephemerides: Theory and Observations of the Moon and Planets. Facultés universitaires Notre Dame de la Paix, Namur, Belgium, 28–31 July, 1980.