Solar Nebula

In this chapter we review recent advances in our understanding of the chemical and isotopic evolution of protoplanetary disks and the solar nebula. Current observational and meteoritic constraints on physical conditions and chemical composition of gas and dust in these systems are presented. A variety of chemical and photochemical processes that occur in planet-forming zones and beyond, in both gas phase and on grain surfaces, are overviewed. The discussion is based upon radio-interferometric, meteoritic, space-born, and laboratory-based observations,measurements and theories. Linkage between cosmochemical and astrochemical data are presented, and interesting research puzzles are discussed.

A major objective of the workshop was to learn about the chemical composition, physical structure, and thermodynamic conditions of the outer parts of the solar nebula where comets formed. Here we sum up what we have learned from years of research about the molecular constituents of comet comae primarily from in situ measurements of Comet 1P/Halley and remote sensing of

Most groups of chondritic meteorites experienced diverse styles of secondary alteration to various degrees that resulted in formation of hydrous and anhydrous minerals (e.g., phyllosilicates, magnetite, carbonates, ferrous olivine, hedenbergite, wollastonite, grossular, and radite, nepheline, sodalite, Fe, Ni-carbides, pentlandite, pyrrhotite, and Ni-rich metal). Mineralogical, petrographic, and isotopic observations suggest that the alteration occurred in the presence of aqueous solutions under

We present millimetre and submillimetre observa- tions of comet C/1995 O1 (Hale-Bopp) undertaken near peri- helion with the Caltech Submillimeter Observatory and the 30- m telescope and Plateau-de-Bure interferometer of the Institut de Radioastronomie Millim´ etrique. From a spectral molecular survey, six new cometary molecular species have been identi- fied for the first time in a comet: SO, SO 2

Abstract— A petrologic and TEM study of a remarkable dark inclusion (DI) in the Ningqiang CV3 chondrite reveals that it is a mixture of highly primitive solar nebula materials. The DI contains two lithologies. The first, lithology A, contains micron-sized olivine and pyroxene grains rimmed by amorphous materials with compositions similar to the underlying crystalline grains. The second, lithology B, appears to preserve the mineralogy of lithology A before formation of the amorphous rims. Overall, the Ningqiang DI appears to record the following processes: 1) formation (condensation and Fe-enrichment) of olivine crystals in the nebula with compositions of Fo42–62; 2) irradiation, resulting in amorphitization of the olivine and pyroxene to varying degrees; 3) partial annealing, resulting in formation of fairly large, euhedral olivine and pyroxene grains with remnant amorphous sharply-bounded rims; 4) in some cases, prolonged annealing, resulting in the formation of microcrystalline olivine or pyroxene rims. The latter annealing would have been a natural consequence of irradiation near the critical temperature for olivine; and 5) mixture of the above materials (lithology A) with nebular condensate high-Ca pyroxene and olivine, which escaped nebular processing, to become lithology B. We suggest that the amorphous rims in lithology A formed in an energetic solar event such as a bi-polar outflow or FU-orionis flare.

Isotopic anomalies in Mo and Zr have recently been reported for bulk chondrites and iron meteorites and have been interpreted in terms of a primordial nucleosynthetic heterogeneity in the solar nebula. We report precise Zr isotopic measurements of carbonaceous, ordinary and enstatite chondrites, eucrites, mesosiderites and lunar rocks. All bulk rock samples yield isotopic compositions that are identical to the

The exploration of the Jovian System and its fascinating satellite Europa is one of the priorities presented in ESA’s “Cosmic Vision” strategic document. The Jovian System indeed displays many facets. It is a small planetary system in its own right, built-up out of the mixture of gas and icy material that was present in the external region of the solar nebula. Through a complex history of accretion, internal differentiation and dynamic interaction, a very unique satellite system formed, in which three of the four Galilean satellites are locked in the so-called Laplace resonance. The energy and angular momentum they exchange among themselves and with Jupiter contribute to various degrees to the internal heating sources of the satellites. Unique among these satellites, Europa is believed to shelter an ocean between its geodynamically active icy crust and its silicate mantle, one where the main conditions for habitability may be fulfilled. For this very reason, Europa is one of the best candidates for the search for life in our Solar System. So, is Europa really habitable, representing a “habitable zone” in the Jupiter system? To answer this specific question, we need a dedicated mission to Europa. But to understand in a more generic way the habitability conditions around giant planets, we need to go beyond Europa itself and address two more general questions at the scale of the Jupiter system: to what extent is its possible habitability related to the initial conditions and formation scenario of the Jovian satellites? To what extent is it due to the way the Jupiter system works? ESA’s Cosmic Vision programme offers an ideal and timely framework to address these three key questions. Building on the in-depth reconnaissance of the Jupiter System by Galileo (and the Voyager, Ulysses, Cassini and New Horizons fly-by’s) and on the anticipated accomplishments of NASA’s JUNO mission, it is now time to design and fly a new mission which will focus on these three major questions. LAPLACE, as we propose to call it, will deploy in the Jovian system a triad of orbiting platforms to perform coordinated observations of its main components: Europa, our priority target, the Jovian satellites, Jupiter’s magnetosphere and its atmosphere and interior. LAPLACE will consolidate Europe’s role and visibility in the exploration of the Solar System and will foster the development of technologies for the exploration of deep space in Europe. Its multi-platform and multi-target architecture, combined with its broadly multidisciplinary scientific dimension, will provide an outstanding opportunity to build a broad international collaboration with all interested nations and space agencies.