From stellar nebula to planetesimals

Context. Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in part the composition of future planets. Aims. The present works aims at determining the chemical composition of icy planetesimals, believed to be similar to present day comets, formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data on chemical composition for models of planetesimals and comets, and models of planet formation and evolution. Methods. We have developed a model that calculates the composition of ices formed during the cooling of the stellar nebula. Coupled with a model of refractory element formation, it allows us to determine the chemical composition and mass ratio of ices to rocks in icy planetesimals throughout in the protoplanetary disc. Results. We provide relationships for ice line positions (for different volatile species) in the disc, and chemical compositions and mass ratios of ice relative to rock for icy planetesimals in stellar systems of solar chemical composition. From an initial homogeneous composition of the nebula, a wide variety of chemical compositions of planetesimals were produced as a function of the mass of the disc and distance to the star. Ices incorporated in planetesimals are mainly composed of H2O, CO, CO2, CH3OH, and NH3. The ice/rock mass ratio is equal to 1 ± 0.5 in icy planetesimals following assumptions. This last value is in good agreement with observations of solar system comets, but remains lower than usual assumptions made in planet formation models, taking this ratio to be of 2–3.

Le Grand Retour ou les Grands Adieux ? Le roman de l’exil chez Kundera

Milan Kundera, an intellectual born in Moravia who emigrated to France in 1975, in L’Ignorance leans on the myth of Ulysses to question contemporary realities of exile and return, nostalgia and oblivion. Does the hope of returning to the place of origin really haunt the modern émigré? To what extent does the notion of homeland still have meaning for him? And what happens when the émigré, unlike Ulysses the great nostalgic, prefers to stay with Calypso his lover rather than return to his native land and faithful wife Penelope? With some cynicism, Kundera in L’Ignorance offers scenarios of exile which desecrate and destabilize historically and culturally available standards while allowing us to reflect on new paradigmatic figures of contemporary exile.

Gas composition of the main volatile elements in protoplanetary discs and its implication for planet formation

Context. Direct observations of gaseous exoplanets reveal that their gas envelope has a higher C/O ratio than that of the host star (e.g., Wasp 12-b). This has been explained by considering that the gas phase of the disc could be inhomogeneous, exceeding the stellar C/O ratio in regions where these planets formed; but few studies have considered the drift of the gas and planet migration. Aims. We aim to derive the gas composition in planets through planet formation to evaluate if the formation of giant planets with an enriched C/O ratio is possible. The study focusses on the effects of different processes on the C/O ratio, such as the disc evolution, the drift of gas, and planet migration. Methods. We used our previous models for computing the chemical composition, together with a planet formation model, to which we added the composition and drift of the gas phase of the disc, which is composed of the main volatile species H2O, CO, CO2, NH3, N2, CH3OH, CH4, and H2S, H2 and He. The study focusses on the region where ice lines are present and influence the C/O ratio of the planets. Results. Modelling shows that the condensation of volatile species as a function of radial distance allows for C/O enrichment in specific parts of the protoplanetary disc of up to four times the solar value. This leads to the formation of planets that can be enriched in C/O in their envelope up to three times the solar value. Planet migration, gas phase evolution and disc irradiation enables the evolution of the initial C/O ratio that decreases in the outer part of the disc and increases in the inner part of the disc. The total C/O ratio of the planets is governed by the contribution of ices accreted, suggesting that high C/O ratios measured in planetary atmospheres are indicative of a lack of exchange of material between the core of a planet and its envelope or an observational bias. It also suggests that the observed C/O ratio is not representative of the total C/O ratio of the planet.

Épilogue de la Divine comédie : l'Enfer un coin du Paradis et incidemment une ame du purgatoire /

Mode of access: Internet.

Pentateuchi versio latina antiquissima e Codice Lugdunensi.

Mode of access: Internet.

Hymnes et proses inédites de Claude Santeul /

Includes index.

Gallia christiana novissima : Histoire des archvêchés, évêchés & abbayes de France; accompagnée des documents authentiques recueillis dans les registres du Vatican et les archives locales.

Vol. 1 originally published. Montbéliard, P. Hoffmann, 1895.

Miracles de Nostre Dame par personnages,

"Un dernier volume ... contiendra une étude sur la date, la patrie et les auteurs du recueil que nous avons imprimé, ainsi que des recherches sur les sources historiques et légendaires des Miracles, et le relevé des leçons du manuscrit que nous avons dû corriger." "Avertissement": v. 8. This projected volume has not been published, 1933.

Tours capitale, la délégation gouvernementale et l'occupation prussienne (1870-1871)

Mode of access: Internet.

Catalogue général des manuscrits des bibliothèques publiques des départements.

No more published of this series. A new series, in octavo, was begun in 1886 under the direction of Ulysse Robert; still in progress (1924) (0412.358)

Recherches historiques sur la folie.

Mode of access: Internet.

Gallia christiana novissima. Histoire des archvêchés, évêchés & abbayes de France, accompagnée des documents authentiques recueillis dans les registres du Vatican et les archives locales.

Vol. 1 originally published. Montbéliard, P. Hoffmann, 1895.

Traité élémentaire du jeu des échecs, contenant la marche et la portée des pièces, les règles, les principes généraux et particuliers, l'analyse des principaux coups et les différens moyens d'attaque et de défense,

Mode of access: Internet.

Pièces dramatiques.

L'intrigant.- Ulysse.- Floricour et Falboire.