Search results for "Formation and evolution of the Solar System"
showing 9 items of 9 documents
Philae's first days on the comet
2015
On 12 November 2014, Philae landed on the surface of comet 67P/Churyumov-Gerasimenko (67P), making an almost 30-year dream a reality. The pioneering flybys of 1P/Halley in 1986 revealed that despite being made primarily of ice, it was covered in highly absorbing carbonrich molecules. What is their composition? When did they form, and through which chemical routes? Might they have constituted prebiotic molecules necessary for life? At a larger scale, what can one learn from comets that has relevance to the evolution of the solar system and planets? ![Figure][1] 12 NOVEMBER 2014: PHILAE LANDED ON THE NUCLEUS OF COMET 67P CREDIT: ESA/ROSETTA/MPS FOR OSIRIS TEAM MPS/UPD/LAM/IAA/SSO/INTA/UPM/DAS…
Protoplanetary Disks, Solar System Minor Bodies and Origin of Life
2001
In the last decade, planetary science researchers have obtained significant advances on the origin and evolution of life on Earth. The increasing resolution and the development of new instruments (as space telescopes and adaptative optics) has provided first detailed images on protoplanetary disks and star formation regions. Moreover, in the last few years, doppler spectroscopic technique has confirmed the presence of extrasolar planets. These evidence shows planetary formation as a continuous and very common process in the Cosmos, indicating that our Solar System is not too special as was suggested in the past.
DIRECT EVIDENCE FOR CONDENSATION IN THE EARLY SOLAR SYSTEM AND IMPLICATIONS FOR NEBULAR COOLING RATES
2009
We have identified in an acid resistant residue of the carbonaceous chondrite Murchison a large number (458) of highly refractory metal nuggets (RMNs) that once were most likely hosted by Ca,Al-rich inclusions (CAIs). While osmium isotopic ratios of two randomly selected particles rule out a presolar origin, the bulk chemistry of 88 particles with sizes in the submicron range determined by energy dispersive X-ray (EDX) spectroscopy shows striking agreement with predictions of single-phase equilibrium condensation calculations. Both chemical composition and morphology strongly favor a condensation origin. Particularly important is the presence of structurally incompatible elements in particl…
An idealized mechanism for the orbital migration of protoplanets
1993
We report here how the action of radiation forces on small solid particles in a circumstellar disc could induce a suitable mechanism for orbital migration of protoplanets. The ratio of radiation-to-gravitational forces acting on a particle depends on its physical and chemical properties. As a consequence of this fact, we show that different particles following the same trajectory would move with different velocities. Sufficiently large bodies, insensitive to radiation forces, would accrete dust particles that are moving more slowly, thus spiralling towards the central star and transporting mass and angular momentum from the outer to the inner parts of the circumstellar disc. In the case of …
Extraterrestrial Mössbauer Spectroscopy
2011
To understand the origin of the Solar system and the origin of Life itself is one of the longest standing goals of human thought. Our Sun and its planets have formed out of an interstellar cloud which collapsed due to gravitational forces, forming a disk shaped so-called protosolar nebula, with the young star in the centre. Such disk shaped and dust grain containing protosolar nebulae have been observed. One of them is surrounding the young star Beta pictoris [1, 2]. Silicates, carbon and metal grains, oxides and sulfides should have been present. One of the important elements with relatively high abundance is iron. It is believed that simple molecules, such as water (H2O), carbon monoxide …
Are high-temperature fractionations in the solar nebula preserved in highly siderophile element systematics of the Earth's mantle?
2004
The relative abundances of the highly siderophile elements (HSE) Os, Ir, Ru, Pt, Rh, and Pd in relatively pristine lherzolites differ from solar abundance ratios and are several orders of magnitude higher than predicted for equilibrium distribution between metal/silicate (core-mantle). The samples are characterized by a mean Ca/Al ratio of 1.18 ± 0.09 σM and a mean Ca/Si ratio of 0.10 ± 0.01 σM, overlapping with a mean Ca/Al of 1.069 ± 0.044 σM and a mean Ca/Si of 0.081 ± 0.023 σM found in chondrites (Wasson and Kallemeyn 1988). Interestingly, the CI-normalized abundance pattern shows decreasing solar system normalized abundances with increasing condensation temperatures. The abundance of …
Water and Geodynamics
2006
Hydrogen is the most abundant element (Fig. 1⇓) in the galaxy and our solar system (Lodders 2003). Therefore it is not astonishing that hydrogen is a key player in the geodynamic evolution of planets. Its fate in the early Earth, after condensation of the solar nebula, the accretion of our planet and hydrogen reprocessing through early asteroidal and cometary bombardment (Dauphas et al. 2000) and segregation of a proto-Earth into iron core and silicate mantle is described elsewhere in this volume (Marty and Yokochi 2006). Figure 1. Abundance of elements in the solar system in numbers of atoms per 106 atoms of silicon (Lodders 2003). This chapter concerns itself with the geodynamics of the m…
Small solar system bodies as granular systems
2017
Asteroids and other Small Solar System Bodies (SSSBs) are currently of great scientific and even industrial interest. Asteroids exist as the permanent record of the formation of the Solar System and therefore hold many clues to its understanding as a whole, as well as insights into the formation of planetary bodies. Additionally, SSSBs are being investigated in the context of impact risks for the Earth, space situational awareness and their possible industrial exploitation (asteroid mining). In all these aspects, the knowledge of the geophysical characteristics of SSSB surface and internal structure are of great importance. Given their size, constitution, and the evidence that many SSSBs ar…
Origin of SiO2-rich components in ordinary chondrites
2006
Abstract Silica-rich objects are common minor components in ordinary chondrites (OC), occurring as fragments and as chondrules. Their typical paragenesis is orthopyroxene + SiO 2 (with bulk SiO 2 >65 wt%) and occasionally with additional olivine and/or spinel. Individual silica-rich components (SRC) have previously been studied in various types of OCs, although there is only one comprehensive study of these objects by Brigham et al. [Brigham, C.A., Murrell, M.T., Yabuki, H., Ouyang, Z., El Goresy, A., 1986. Silica-bearing chondrules and clasts in ordinary chondrites. Geochim. Cosmochim. Acta 50, 1655–1666]. Several different explanations of how SRCs formed have been published. The main ques…