The 2011 October Draconids Outburst. II. Meteoroid Chemical Abundances from Fireball Spectroscopy

On October 8, 2011 the Earth crossed dust trails ejected from comet 21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to an outburst in the activity of the October Draconid meteor shower, and an international team was organized to analyze this event. The SPanish Meteor Network (SPMN) joined this initiative and recorded the October Draconids by means of low light level CCD cameras. In addition, spectroscopic observations were carried out. Tens of multi-station meteor trails were recorded, including an extraordinarily bright October Draconid fireball (absolute mag. -10.5) that was simultaneously imaged from three SPMN meteor ob-serving stations located in Andalusia. Its spectrum was obtained, showing a clear evolution in the relative intensity of emission lines as the fireball penetrated deeper into the atmosphere. Here we focus on the analysis of this remarkable spectrum, but also discuss the atmospheric trajectory, atmospheric penetration, and orbital data computed for this bolide which was probably released during 21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed together with the tensile strength for the October Draconid meteoroids. The chemical profile evolution of the main rocky elements for this extremely bright bolide is compared with the elemental abundances obtained for 5 October Draconid fireballs also recorded during our spectroscopic campaign but observed only at a single station. Significant chemical heterogeneity between the small meteoroids is found as we should expect for cometary aggregates being formed by diverse dust components.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical Society. Accepted for publication in MNRAS on April 28th, 2013 Manuscript Pages: 28 Tables: 5 Figures: 12. Manuscript associated: "The 2011 October Draconids outburst. I. Orbital elements, meteoroid fluxes and 21P/Giacobini-Zinner delivered mass to Earth" by Trigo-Rodriguez et al. is also in press in the same journa

Excitations in the quantum paramagnetic phase of the quasi-one-dimensional Ising magnet CoNb2_2O6_6 in a transverse field: Geometric frustration and quantum renormalization effects

The quasi-one-dimensional (1D) Ising ferromagnet CoNb$_2$O$_6$ has recently been driven via applied transverse magnetic fields through a continuous quantum phase transition from spontaneous magnetic order to a quantum paramagnet, and dramatic changes were observed in the spin dynamics, characteristic of weakly perturbed 1D Ising quantum criticality. We report here extensive single-crystal inelastic neutron scattering measurements of the magnetic excitations throughout the three-dimensional (3D) Brillouin zone in the quantum paramagnetic phase just above the critical field to characterize the effects of the finite interchain couplings. In this phase, we observe that excitations have a sharp, resolution-limited line shape at low energies and over most of the dispersion bandwidth, as expected for spin-flip quasiparticles. We map the full bandwidth along the strongly dispersive chain direction and resolve clear modulations of the dispersions in the plane normal to the chains, characteristic of frustrated interchain couplings in an antiferromagnetic isosceles triangular lattice. The dispersions can be well parametrized using a linear spin-wave model that includes interchain couplings and further neighbor exchanges. The observed dispersion bandwidth along the chain direction is smaller than that predicted by a linear spin-wave model using exchange values determined at zero field, and this effect is attributed to quantum renormalization of the dispersion beyond the spin-wave approximation in fields slightly above the critical field, where quantum fluctuations are still significant.Comment: 11 pages, 6 figures. Updated references. Minor changes to text and figure

Las playas dentro del Manejo Integrado Costero

El objetivo de este trabajo es la presentación del modelo de Manejo Integrado Costero (MIC) y su aplicación específica en las áreas de playa. Se inicia con un breve recuento de la evolución del MIC desde 1972, cuando Estados Unidos promulga la Coastal Zone Management Act, hasta la actualidad. Luego se describen los conceptos centrales de holismo y su relación con el modelo de Desarrollo Sostenible, con miras a definir un enfoque sistémico del manejo en las costas. A continuación se describen los fundamentos del MIC con base en tres componentes: l. El objeto del MIC; 2. El objetivo del MIC; y 3. Las fases de los planes de MIC. Con el marco general claro, se describe en detalle las características principales de las playas desde su gestión: a. Condición de bien de uso público; b. Alta dinámica energética natural; c. Turismo como actividad principal; y d. Necesidad de un órgano exclusivo para su gestión. También se representan las tres dimensiones del desarrollo sostenible en el espacio de playa, como ejercicio de aplicación del modelo imperante. Por último, se presentan algunas herramientas de gestión de playas, como la capacidad de carga, las certificaciones ambientales y las clasificaciones de playas.The objective of this work is the presentation of the Integrated Coastal Management model (ICM) and its specific application in beach areas. It begins with a brief account of the evolution of the ICM since 1972, when the United States enacted the Coastal Zone Management Act, to the present. It then describes the core concepts of holism and its relation to the sustainable development model in order to define a systemic approach to the coast management. The following describes the fundamentals of IMC based on three components: l. the object of ICM 2. the aim of the ICM, and 3. the phases of ICM plans. With clear framework, we describe in detail the main features of the beaches from its management: a. public asset condition b. high dynamic natural energy c. tourism as a main activity, and d. need for a unique management body. Also, the three dimensions of beach sustainable development are described, as an exercise for the application of the prevailing model. Finally, we present some beach management tools, such as carrying capacity, environmental certifications and classifications of beaches

Water-ice driven activity on Main-Belt Comet P/2010 A2 (LINEAR) ?

The dust ejecta of Main-Belt Comet P/2010 A2 (LINEAR) have been observed with several telescopes at the at the Observatorio del Roque de los Muchachos on La Palma, Spain. Application of an inverse dust tail Monte Carlo method to the images of the dust ejecta from the object indicates that a sustained, likely water-ice driven, activity over some eight months is the mechanism responsible for the formation of the observed tail. The total amount of dust released is estimated to be 5E7 kg, which represents about 0.3% of the nucleus mass. While the event could have been triggered by a collision, this cannot be decided from the currently available data.Comment: Accepted for ApJ Letter

EP-1270: Volumetric modulated arc therapy in high-risk neuroblatoma¥s treatment. Single institucional experience

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