Astrochemistry

We investigate the spectral evolution of the cataclysmic stellar object V339 Delphini (Nova Del 2013), using observations made at "Amiral Vasile Urseanu" Astronomical Observatory (A92) in Bucharest, and Stardreams Observatory (L16) in Vǎ lenii de Munte, Romania, between August 2013 and October 2014. Starting with the official announcement on August 14th, 2013, we obtained spectroscopic and photometric data using 0.3 m Schmidt-Cassegrain and respectively 0.2 m Ritchey-Chretien telescopes equipped with Alpy 600 spectrograph. We determined that V339 Del is a Fe II type nova with strong Fe II and P Cygni lines in the aftermath of the cataclysmic event, variable Balmer and Fe II lines intensities and a continuous but slow spectral evolution.

Laboratory astrophysics is the Rosetta Stone that enables astronomers to understand and interpret the distant cosmos. It provides the tools to interpret and guide astronomical observations and delivers the numbers needed to quantitatively model the processes taking place in space, providing a bridge between observers and modelers. IAU Symposium 350 was organized by the International Astronomical Union's Laboratory Astrophysics Commission (B5), and was the first topical symposium on laboratory astrophysics sponsored by the IAU. Active researchers in observational astronomy, space missions, experimental and theoretical laboratory astrophysics, and astrochemistry discuss the topics and challenges facing astronomy today. Five major topics are covered,
spanning from star- and planet-formation through stellar populations to extragalactic chemistry and dark matter. Within each topic, the main themes of
laboratory studies, astronomical observations, and theoretical modeling are explored, demonstrating the breadth and the plurality of disciplines engaged in the growing  eld of laboratory astrophysics.

Proyecto de unificación  basado en la simetría especular de fuerza y en la simetría de fuerzas de interacción de cargas. Dicha en simetrías predicen la existencias de cargas Gauge. También se describe la verdadera naturaleza de la fuerza gravitacional, el big bang y su evolución, materia y energía oscura, el origen de la dualidad onda partícula etc.

Acoplamiento de la simetría FIC a la simetría Kaluza-Klein para una nueva teoría de cuerdas de 11 dimensiones (teoría M) dando una posible explicación a la asimetría de materia en el universo.

Can radioactive atoms in a sealed test tube create living cells in a second sealed, sterile test tube containing chemical building blocks of life? This question may be answered in the affirmative by experiments designed to test a new scientific hypothesis about the origin of life, based on the ideas of a modern spiritual master. The hypothesis to be tested is based on the concept of microvita, subtle subatomic living entities that spread life and minds throughout the universe. Microvita were introduced in India by the guru of Ananda Marga, Prabhat Ranjan Sarkar, in 1986.

We report Mopra Australia Telescope National Facility (ATNF), Anglo-Australian Telescope and Atacama Submillimeter Telescope Experiment observations of a molecular clump in Carina, BYF73 = G286.21+0.17, which give evidence of large-scale gravitational infall in the dense gas. From the millimetre and far-infrared data, the clump has a mass of ~2 × 104Msolar, luminosity of ~2-3 × 104Lsolar and diameter of ~0.9 pc. From radiative transfer modelling, we derive a mass infall rate of ~3.4 × 10-2Msolaryr-1. If confirmed, this rate for gravitational infall in a molecular core or clump may be the highest yet seen. The near-infrared K-band imaging shows an adjacent compact HII region and IR cluster surrounded by a shell-like photodissociation region showing H2 emission. At the molecular infall peak, the K imaging also reveals a deeply embedded group of stars with associated H2 emission. The combination of these features is very unusual, and we suggest that they indicate the ongoing formation ...

The chemical mechanism of the 1PN formation was successfully studied by using the CCSD(T)/6-311++G(3df,3pd) level of theory. The 1NH3 + 3PH and 4P + NH3 reaction paths are not energetically favorable to form the 1PN molecule. However, the 3NH + 3PH, 4N + 3PH3, 4N + 3PH, 4P + 3NH, and 4P + 2NH2 reaction paths to form the 1PN molecule are only energetically favorable by taking place through specific
transition states to form the 1PN molecule. The NH3 + 3PH, 4N + 1PH3, NH3 + 4P, and 4N + 2PH2 reactions are spin-forbidden and the probability of hopping for these reactions was estimated to be 0 by the Landau–Zener theory. This is the first detailed study on the chemical mechanism for the 1PN formation

Low mass stars, like our Sun, are born from the collapse of a molecular cloud. The matter falls in the center of the cloud, creating a protoplanetary disk surrounding a protostar. Planets and other solar system bodies will be formed in the disk.The chemical composition of the interstellar matter and its evolution during the formation of the disk are important to better understand the formation process of these objects.I studied the chemical and physical evolution of this matter, from the cloud to the disk, using the chemical gas-grain code Nautilus.A sensitivity study to some parameters of the code (such as elemental abundances and parameters of grain surface chemistry) has been done. More particularly, the updates of rate coefficients and branching ratios of the reactions of our chemical network showed their importance, such as on the abundances of some chemical species, and on the code sensitivity to others parameters.Several physical models of collapsing dense core have also been considered. The more complex and solid approach has been to interface our chemical code with the radiation-magneto-hydrodynamic model of stellar formation RAMSES, in order to model in three dimensions the physical and chemical evolution of a young disk formation. Our study showed that the disk keeps imprints of the past history of the matter, and so its chemical composition is sensitive to the initial conditions.

There is solid evidence for the occurrence of large amounts of organic material in the cosmos, particularly in the form of aromatic compounds. These molecules can be found on the surface of Earth and Mars, in the atmospheres of the larger planets and on many of their satellites, on asteroids, comets, meteorites, the atmospheres of red giant stars, interstellar nebulae, and in the spiral arms of galaxies. Many of these environments are expected to be of low temperature and pressure, implying that the Gibb's free energy for the formation of these complex molecules should be positive and large, suggesting that their existence could only be attributed to non-equilibrium thermodynamic processes. In this article we first review the evidence for the abundance of these molecules in the cosmos and then describe how the ubiquity can be explained from within the framework of non-equilibrium thermodynamics on the basis of the catalytic properties of these pigment molecules in dissipating photons of the ultraviolet and visible emission spectra of neighboring stars, leading to greater local entropy production. A relation between the maximum wavelength of absorption of these organic pigments and the corresponding stellar photon environment provides a guide to determining which aromatic compounds are most probable in a given stellar neighborhood, a postulate that can be verified on Earth. It is suggested that at least some of the baryonic dark matter may be associated with these molecules which emit in the extreme infrared with many, but weak, emission lines, thus so far escaping detection. This thermodynamic explanation for the ubiquity of these organic molecules also has relevance to the possibility of life, both as we know it, and as we may not know it, throughout the universe.

Titan, the largest satellite of Saturn, has a thick atmosphere containing nitrogen and methane. A variety of organic compounds have been detected in the atmosphere, most likely produced when atmospheric gases are exposed to ultraviolet light, electrons captured by the magnetosphere of Saturn and cosmic rays. The Cassini/Huygens probe showed that the average temperature on the surface of Titan is 93.7 K, with lakes of liquid ethane and methane. Sub-surface mixtures of liquid ammonia and water may also be present. We have synthesized complex organic compounds (tholins) by exposing a mixture of nitrogen and methane to plasma discharges, and investigated their interactions with several different liquids that simulate Titan's liquidosphere. We found that coacervates formed when tholins were extracted in non-polar solvents followed by exposure to aqueous ammonia solutions. The results suggest that coacervates can self-assemble in Titan's liquidosphere which have the potential to undergo further chemical evolution. Similar processes are likely to occur in the early evolution of habitable planets when tholin-like compounds undergo phase separation into microscopic structures dispersed in a suitable aqueous environment.(Received January 30 2013)(Accepted March 21 2013)

En este artículo se discuten las condiciones necesarias para originar vida compleja a partir de ADN con un perfil bioquímico similar al humano y se propone un nuevo enfoque a la búsqueda de exoplanetas debido a la inviabilidad de complejos moleculares orgánicos en planetas pertenecientes a estrellas tipo M. Una vez recolectados todos los parámetros necesarios para dar origen a vida compleja, se procedió a crear una fórmula en base a la Ecuación de Drake que permitiera entregar una estimación de la potencial cantidad de civilizaciones inteligentes que pueden tener origen en la Vía Láctea a día de hoy.

In this paper we present the survey of some applications for mobile devices that can be used for the teaching of astrochemistry by teachers and students. From a methodological point of view, this research is exploratory and approach nature qualitative. The results present some possibilities of using these resources, however difficulties are perceived for its use and posteriorly contribution in the teaching of astrochemistry. We consider the valid results, because they should stimulate the reflection of chemistry teachers on the need to develop pedagogical practices able to supply the specificities related to the teaching and
learning process of astrochemistry with the use of mobile resources.

We present a millimetre molecular line survey of seven high mass loss rate carbon stars in both the northern and southern skies. A total of 196 emission lines (47 transitions) from 24 molecular species were detected. The observed CO emission is used to determine mass-loss rates and the physical structure of the circumstellar envelope, such as the density and temperature structure, using a detailed radiative transfer analysis. This enables abundances for the remaining molecular species to be determined. The derived abundances generally vary between the sources by no more than a factor of five indicating that circumstellar envelopes around carbon stars with high mass-loss rates have similar chemical compositions. However, there are some notable exceptions. The most striking difference between the abundances are reflecting the spread in the 12C/13C-ratio of about an order of magnitude between the sample stars, mainly reflecting the results of nucleosynthesis. The abundance of SiO also shows a variation of more than an order of magnitude between the sources and is on the average more than an order of magnitude more abundant than predicted from photospheric chemistry in thermal equilibrium. The over abundance of SiO is consistent with dynamical modelling of the stellar atmosphere and the inner parts of the wind where a pulsation-driven shock has passed. This scenario is possibly further substantiated by the relatively low amount of CS present in the envelopes. The chemistry occurring in the outer envelope is consistent with current photochemical models.

Accurate photodissociation cross sections have been computed for transitions from the X 1 Σ + ground electronic state of CS to six low-lying excited electronic states. New ab initio potential curves and transition dipole moment functions have been obtained for these computations using the multi-reference configuration interaction approach with the Davidson correction (MRCI+Q) and aug-cc-pV6Z basis sets. State-resolved cross sections have been computed for transitions from nearly the full range of rovibrational levels of the X 1 Σ + state and for photon wavelengths ranging from 500 Å to threshold. Destruction of CS via predissociation in highly excited electronic states originating from the rovibrational ground state is found to be unimportant. Photodissociation cross sections are presented for temperatures in the range between 1000 and 10,000 K, where a Boltzmann distribution of initial rovibrational levels is assumed. Applications of the current computations to various astrophysical environments are briefly discussed focusing on photodissociation rates due to the standard interstellar and blackbody radiation fields.

Environmental contextPerfluoroalkyl compounds are organic contaminants that exhibit strong resistance to chemical- and microbial-degradation. As partitioning between solid and aqueous phases is expected to control the transport of perfluoroalkyl compounds, we studied the molecular mechanisms of their adsorption–desorption at a representative Fe oxide surface using in situ molecular spectroscopy. The results provide valuable information on the types of bonds formed, and enable a better understanding of the transport and fate of these organic contaminants in natural environments. The kinetics and mechanisms of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) adsorption to nanoparticulate hematite (α-Fe2O3) from aqueous solutions were examined using in situ, flow-through attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. Results indicate that both PFOA and PFOS molecules are retained at the hydrophilic hematite surface and the adsorptio...

Environmental context Novel technology is used to examine oil contaminated soil to better understand this longstanding problem. The data indicate that oil forms a non-discriminant layer over all the soil components, which in their natural state would be exposed to water, and that it retains certain polar compounds while contributing other oil contaminants to the surrounding porewater and groundwater. Such molecular level information helps to better understand the reoccurrence of hydrophobicity in remediated soil, and could lead to novel clean-up methods. Comprehensive multiphase (CMP) NMR spectroscopy is a novel NMR technology introduced in 2012. CMP NMR spectroscopy permits the analysis of solid, gel and liquid phases in unaltered natural samples. Here the technology is applied to control and oil contaminated soils to understand the molecular processes that give rise to non-wettable soils. 13C solid-state NMR spectroscopy is found to be excellent for studying the bulk rigid compone...

We present the first analysis of far-ultraviolet reflectance spectra of regions on Rhea's leading and trailing hemispheres collected by the Cassini Ultraviolet Imaging Spectrograph during targeted flybys. In particular, we aim to explain the unidentified broad absorption feature centred near 184 nm. We have used laboratory measurements of the UV spectroscopy of a set of candidate molecules and found a good fit to Rhea's spectra with both hydrazine monohydrate and several chlorine-containing molecules. Given the radiation-dominated chemistry on the surface of icy satellites embedded within their planets' magnetospheres, hydrazine monohydrate is argued to be the most plausible candidate for explaining the absorption feature at 184 nm. Hydrazine was also used as a propellant in Cassini's thrusters, but the thrusters were not used during icy satellite flybys and thus the signal is believed to not arise from spacecraft fuel. We discuss how hydrazine monohydrate may be chemically produced on icy surfaces.

We report Mopra Australia Telescope National Facility (ATNF), Anglo-Australian Telescope and Atacama Submillimeter Telescope Experiment observations of a molecular clump in Carina, BYF73 = G286.21+0.17, which give evidence of large-scale gravitational infall in the dense gas. From the millimetre and far-infrared data, the clump has a mass of ~2 × 104Msolar, luminosity of ~2-3 × 104Lsolar and diameter of ~0.9 pc. From radiative transfer modelling, we derive a mass infall rate of ~3.4 × 10-2Msolaryr-1. If confirmed, this rate for gravitational infall in a molecular core or clump may be the highest yet seen. The near-infrared K-band imaging shows an adjacent compact HII region and IR cluster surrounded by a shell-like photodissociation region showing H2 emission. At the molecular infall peak, the K imaging also reveals a deeply embedded group of stars with associated H2 emission. The combination of these features is very unusual, and we suggest that they indicate the ongoing formation of a massive star cluster. We discuss the implications of these data for competing theories of massive star formation.

Environmental context Ozone pollution in Houston, Texas, has been a public health concern for decades. Unusually large hourly changes in observed ozone concentrations have been correlated with a greater likelihood of violating the federal air quality standard. We investigate the geographic and chemical origins of these large hourly increases, which should help regulators better control ozone violations. Many of Houston’s highest 8-h ozone (O3) peaks are characterised by increases in concentrations of at least 40ppb in 1h, or 60ppb in 2h. These rapid increases are called non-typical O3 changes (NTOCs). In 2004, the Texas Commission on Environmental Quality (TCEQ) developed a novel emissions control strategy aimed at eliminating NTOCs. The strategy limited routine and short-term emissions of ethene, propene, 1,3-butadiene and butene isomers, collectively called highly reactive volatile organic compounds (HRVOCs), which are released from petrochemical facilities. HRVOCs have been assoc...

Environmental context. The release of mining effluents exposes natural waters to excess metals and thereby threatens both human and environmental health. The present study explores the toxicity of aqueous mining effluents collected from a mining area in Sudbury (Ontario, Canada), using two different methods for determination of metal speciation, and an algal toxicity study. The results show reasonable correlation between metal speciation and the observed toxicity and suggest the importance of taking into account other factors related to water quality criteria such as nutrient concentrations, diluent water and presence of other toxic metals that can greatly influence the toxicological result. . The present study explores the toxicity of aqueous mining and municipal effluents from the Sudbury area (Canada) using equilibrium- and kinetics-based estimates of metal speciation and chronic toxicity studies using algae (Pseudokirchneriella subcapitata). Free metal ion concentration was dete...