Infrared Observations of novae in the SOFIA era

Classical novae inject chemically enriched gas and dust into the local inter-stellar medium (ISM). Abundances in the ejecta can be deduced from infrared (IR) forbidden line emission. IR spectroscopy can determine the mineralogy of grains that grow in nova ejecta. We anticipate the impact that NASA's new Stratospheric Observatory for Infrared Astronomy (SOFIA) will have on future IR studies of novae.Comment: To appear in the proceedings of "Physics of Evolved Stars 2015 - A conference dedicated to the memory of Olivier Chesneau

The circumstellar dust of "Born-Again" stars

We describe the evolution of the carbon dust shells around Very Late Thermal Pulse (VLTP) objects as seen at infrared wavelengths. This includes a 20-year overview of the evolution of the dust around Sakurai's object (to which Olivier made a seminal contribution) and FG Sge. VLTPs may occur during the endpoint of as many as 25% of solar mass stars, and may therefore provide a glimpse of the possible fate of the Sun.Comment: To appear in the proceedings of "Physics of Evolved Stars 2015 - A conference dedicated to the memory of Olivier Chesneau

LANDSAT follow-on: A report by the applications survey groups. Volume 1: Executive summary

Attempts at operational usage of the LANDSAT imagery by non NASA users are studied with particular emphasis on profitable use of the imagery, as contrasted with investigations concerned with research and development of a technology. An evaluation is given of the functional capabilities of the LANDSAT follow-on and ground systems designs in terms of user requirements and desiderata for data measurements, products, and parameters. Applications survey groups (ASGs) were formed for mineral and petroleum exploration, inland water resources, land inventory, and agriculture. The members were drawn from all segments of the user community: Federal agencies, state and local governments or agencies (or from associations of such constituencies), industry and universities. They were selected so that in aggregate they would be able to adequately assess the state-of-the-art in their technical areas and represent this in the ASG deliberations

Thermodynamic Properties of Kagome Antiferromagnets with different Perturbations

We discuss the results of several small perturbations to the thermodynamic properties of Kagome Lattice Heisenberg Model (KLHM) at high and intermediate temperatures, including Curie impurities, dilution, in-plane and out of plane Dzyaloshinski-Moria (DM) anisotropies and exchange anisotropy. We examine the combined role of Curie impurities and dilution in the behavior of uniform susceptibility. We also study the changes in specific heat and entropy with various anisotropies. Their relevance to newly discovered materials ZnCu3(OH)6Cl2 is explored. We find that the magnetic susceptibility is well described by about 6 percent impurity and dilution. We also find that the entropy difference between the material and KLHM is well described by the DM parameter D_z/J~0.1.Comment: 6 pages, 3 figures, proceedings of the HFM 2008 Conferenc

Faculty Perceptions of Differences between Teaching Rural Appalachian and Urban Social Work Students

Faculty who teach social work students in both rural Appalachian colleges and urban settings often notice differences in how these students approach learning and respond to the classroom environment and university setting. There is limited research on how Appalachian college students experience higher education and how they perceive the benefits of a college degree. This qualitative study explored the perceptions of social work faculty members at three Appalachian and three Midwestern universities, who have taught rural Appalachian students, as well as students from urban areas. Findings indicated that faculty mostly viewed Appalachian students as being different from urban students. Appalachian social work students often focused on the practical aspects of learning, but like many urban students they were intuitive, creative, and adept at problem-solving and critical thinking. Rural students were more inclined to benefit from practice methods oriented toward rural practice. Implications for practice are discussed with an emphasis on faculty members being aware of Appalachian culture and, in turn, directing their teaching style and methods to possible learning differences

Pressure-induced Spin-Peierls to Incommensurate Charge-Density-Wave Transition in the Ground State of TiOCl

The ground state of the spin-Peierls system TiOCl was probed using synchrotron x-ray diffraction on a single-crystal sample at T = 6 K. We tracked the evolution of the structural superlattice peaks associated with the dimerized ground state as a function of pressure. The dimerization along the b axis is rapidly suppressed in the vicinity of a first-order structural phase transition at Pc = 13.1(1) GPa. The high-pressure phase is characterized by an incommensurate charge density wave perpendicular to the original spin chain direction. These results show that the electronic ground state undergoes a fundamental change in symmetry, indicating a significant change in the principal interactions.Comment: 5 pages, 4 figure

A very luminous, highly extinguished, very fast nova - V1721 Aquilae

Fast novae are primarily located within the plane of the Galaxy, slow novae are found within its bulge. Because of high interstellar extinction along the line of sight many novae lying close to the plane are missed and only the brightest seen. One nova lying very close to the Galactic plane is V1721 Aquilae, discovered in outburst on 2008 September 22. Spectra obtained 2.69 days after outburst revealed very high expansion velocities (FWHM ~6450 km/s). In this paper we have used available pre- and post-outburst photometry and post-outburst spectroscopy to conclude that the object is a very fast, luminous, and highly extinguished A_V=11.6+/-0.2) nova system with an average ejection velocity of ~3400 km/s. Pre-outburst near-IR colours from 2MASS indicate that at quiescence the object is similar to many quiescent CNe and appears to have a main sequence/sub-giant secondary rather than a giant. Based on the speed of decline of the nova and its emission line profiles we hypothesise that the axis ratio of the nova ejecta is ~1.4 and that its inclination is such that the central binary accretion disc is face-on to the observer. The accretion disc's blue contribution to the system's near-IR quiescent colours may be significant. Simple models of the nova ejecta have been constructed using the morphological modelling code XS5, and the results support the above hypothesis. Spectral classification of this object has been difficult owing to low S/N levels and high extinction, which has eliminated all evidence of any He/N or FeII emission within the spectra. We suggest two possibilities for the nature of V1721 Aql: that it is a U Sco type RN with a sub-giant secondary or, less likely, that it is a highly energetic bright and fast classical nova with a main sequence secondary. Future monitoring of the object for possible RN episodes may be worthwhile, as would archival searches for previous outbursts.Comment: 9 pages 10 figures, accepted for publication in A&A. Abstract has been slightly shortened from published versio