A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite I. The observational data

Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions by H2O and O2 in the terrestrial atmosphere. The purpose of the measurements presented here is to cover wavelength regions at and around 0.55 mm -- regions largely unobservable from the ground. Using the Odin astronomy/aeronomy satellite, we performed the first spectral survey of the Orion KL molecular cloud core in the bands 486--492 and 541--576 GHz with rather uniform sensitivity (22--25 mK baseline noise). Odin's 1.1 m size telescope, equipped with four cryo-cooled tuneable mixers connected to broad band spectrometers, was used in a satellite position-switching mode. Two mixers simultaneously observed different 1.1 GHz bands using frequency steps of 0.5 GHz (25 hours each). An on-source integration time of 20 hours was achieved for most bands. The entire campaign consumed ~1100 orbits, each containing one hour of serviceable astro-observation. We identified 280 spectral lines from 38 known interstellar molecules (including isotopologues) having intensities in the range 80 to 0.05 K. An additional 64 weak lines remain unidentified. Apart from the ground state rotational 1(1,0)--1(0,1) transitions of ortho-H2O, H218O and H217O, the high energy 6(2,4)--7(1,7) line of para-H2O and the HDO(2,0,2--1,1,1) line have been observed, as well as the 1,0--0,1 lines from NH3 and its rare isotopologue 15NH3. We suggest assignments for some unidentified features, notably the new interstellar molecules ND and SH-. Severe blends have been detected in the line wings of the H218O, H217O and 13CO lines changing the true linewidths of the outflow emission.Comment: 21 pages, 10 figures, 7 tables, accepeted for publication in Astronomy and Astrophysics 30 August 200

RETRATO SIN IDENTIFICAR [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Identifiable Acetylene Features Predicted for Young Earth-like Exoplanets with Reducing Atmospheres Undergoing Heavy Bombardment

The chemical environments of young planets are assumed to be largely influenced by the impacts of bodies lingering on unstable trajectories after the dissolution of the protoplanetary disk. We explore the chemical consequences of impacts within the context of reducing planetary atmospheres dominated by carbon monoxide, methane, and molecular nitrogen. A terawatt high-power laser was selected in order to simulate the airglow plasma and blast wave surrounding the impactor. The chemical results of these experiments are then applied to a theoretical atmospheric model. The impact simulation results in substantial volume mixing ratios within the reactor of 5% hydrogen cyanide (HCN), 8% acetylene (C2H2), 5% cyanoacetylene (HC3N), and 1% ammonia (NH3). These yields are combined with estimated impact rates for the early Earth to predict surface boundary conditions for an atmospheric model. We show that impacts might have served as sources of energy that would have led to steady-state surface quantities of 0.4% C2H2, 400 ppm HCN, and 40 ppm NH3. We provide simulated transit spectra for an Earth-like exoplanet with this reducing atmosphere during and shortly after eras of intense impacts. We predict that acetylene is as observable as other molecular features on exoplanets with reducing atmospheres that have recently gone through their own "heavy bombardments," with prominent features at 3.05 and 10.5 μm

Magnetobiochronology of lower Pliocene marine sediments from the lower Guadalquivir Basin: insights into the tectonic evolution of the Strait of Gibraltar area

The Gibraltar Arc is a complex tectonic region, and several competing models have been proposed to explain its evolution. We studied the sedimentary fill of the Guadalquivir Basin to identify tectonic processes that were occurring when the reopening of the Strait of Gibraltar led to the reestablishment of Mediterranean outflow. We present a chronostratigraphic framework for the Lower Pliocene sediments from the lower Guadalquivir Basin (SW Spain). The updated chronology is based on magnetobiostratigraphic data from several boreholes. Our results show that the studied interval in the La Matilla core is in the early Pliocene section, providing better constraints on the sedimentary evolution of the basin during that period. Migrating depositional facies led to a younger onset of sandy deposition basinward. At the northwestern passive margin, a 0.7 m.y. period of sedimentary bypass related to a sharp decrease in sedimentation rates and lower sea levels resulted from the tectonic uplift of the forebulge. In contrast, high sedimentation rates with continuous deep-marine sedimentation are recorded at the basin center due to continuous tectonic subsidence and west-southwestward progradation of axial depositional systems. The marginal forebulge uplift, continuous tectonic basinal subsidence, and southward progradation of clinoforms in the early Pliocene can be explained by the pull of a lithospheric slab beneath the Gibraltar Arc as the Strait of Gibraltar opened. These findings are, to our knowledge, the first reported sedimentary expression of slab pull beneath the Betics related to the opening of the Strait of Gibraltar after the Messinian salinity crisis

Further evidence for a relatively high sea level during the penultimate interglacial: open-system U-series ages from La Marina (Alicante, East Spain)

The elevation and timing of high sea stands during Oxygen Isotope Stage (OIS) 7 are not as well constraíned as those of OIS 5e. Conflictíng values are reported from Medíterranean coastlines, and fossil dating is inaccurate because of ubiquitous open U-series systems. New morphostratigraphic data from La Marina (eastem Spain) supported by open-system U-series coral ages shed light on the maximum sea level duríng OIS 7. Fossil corals (Cladocora Caespitosa) underlying an OIS 5e marine unít yielded U-series ages from 178 ± (0 to 208 ± 1) ka (± 20σ n=7) with an outlier al 240 ± 18 ka. Mean open-system limit ages of 170 ± 10 (minimum age after correction for 234Th-230Th uptake) and 237 ± 20 ka (maximum ase after correction for 238U - 234U uptake) were calculated to have a probable age closer to the minimum value, for an assignment of OlS 7a or 7c. The occurrence of a warn-water "Senegalese" fauna (Strombus bubonius) in OIS5e and OIS 7 marine units confirms the arrival of tropical species to the Mediterranean before the last interglacial periodo Morpho-sedimentological and neotectonic studies suggest that the maximum paleo-sea level during OIS 7c or 7a was a few melers below that of OlS Se

Réalisation et caractérisation de dépôts microniques de composés à haut indice de réfraction,à base de sels de zinc,sur des particules de carbonate de calcium

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Search for C-2(-) in diffuse clouds

A search has been carried out for the C2- ion in diffuse clouds toward HD 23180, HD 24912, HD 24398, HD 46711, and HD 50064 using the HIDES spectrometer on the Okayama 188-cm telescope. An upper limit of 8.3 * 1010-1.8 * 1012 cm-2 was obtained for the C2- column density. The upper limit value (3.8 * 1011 cm-2) toward HD 23180 is two orders of magnitude smaller than that of the C2 radical. Possible production mechanisms for C2- are discussed

Tunable midinfrared semiconductor lasers for laser spectroscopy

International audienc

Malacology, foraminifers and paleogeography ¡n the Upper Neogene of the Bou Regreg Basin (W of Morocco)

The molluscs and foraminiferids comunnities of three representatives sections (Dar Bel Amri, Oued Arjat and Salé) of de Upper Neogene of the Bou Regreg Basin are studied. The paleontological results reflected changes in the benthic communities, which are shallower from the East to the West, and from the Miocene to the Pliocene. The stratigraphy and sedimentoiogy are according with the paleontological result

Tunable midinfrared semiconductor lasers for laser spectroscopy

International audienc