Confirmation of SBS 1150+599A As An Extremely Metal-Poor Planetary Nebula

SBS 1150+599A is a blue stellar object at high galactic latitude discovered in the Second Byurakan Survey. New high-resolution images of SBS 1150+599A are presented, demonstrating that it is very likely to be an old planetary nebula in the galactic halo, as suggested by Tovmassian et al (2001). An H-alpha image taken with the WIYN 3.5-m telescope and its "tip/tilt" module reveals the diameter of the nebula to be 9.2", comparable to that estimated from spectra by Tovmassian et al. Lower limits to the central star temperature were derived using the Zanstra hydrogen and helium methods to determine that the star's effective temperature must be > 68,000K and that the nebula is optically thin. New spectra from the MMT and FLWO telescopes are presented, revealing the presence of strong [Ne V] lambda 3425, indicating that the central star temperature must be > 100,000K. With the revised diameter, new central star temperature, and an improved central star luminosity, we can constrain photoionization models for the nebula significantly better than before. Because the emission-line data set is sparse, the models are still not conclusive. Nevertheless, we confirm that this nebula is an extremely metal-poor planetary nebula, having a value for O/H that is less than 1/100 solar, and possibly as low as 1/500 solar.Comment: 19 pages, 6 figures. Accepted for publication in the Astronomical Journa

Whole Earth Telescope Observations of the Helium Interacting Binary PG 1346+082 (CR Bootis)

We present our analysis of 240 hr of white-light, high-speed photometry of the dwarf nova-like helium variable PG 1346+082 (CR Boo). We identify two frequencies in the low-state power spectrum, at 679.670 ± 0.004 μHz and 669.887 ± 0.008 μHz. The 679.670 μHz variation is coherent over at least a 2 week time span, the first demonstration of a phase-coherent photometric variation in any dwarf nova-like interacting binary white dwarf system. The high-state power spectrum contains a complex fundamental with a frequency similar, but not identical, to the low-state spectrum, and a series of harmonics not detected in low state. We also uncover an unexpected dependence of the high-frequency power\u27s amplitude and frequency structure on overall system magnitude. We discuss these findings in light of the general AM CVn system model, particularly the implications of the high-order harmonics on future studies of disk structure, mass transfer, and disk viscosity

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Anales del Instituto Español de Edafología, Ecología y Fisiología Vegetal Tomo 6

[Volumen 1] Mariano Claver Aliod / Contribución al estudio de los suelos salícico-húmicos de la Sierra de Guadarrama.-- Enrique Gutiérrez Ríos y Lorenzo Hernando / Yacimientos de hentonita en Marruecos Español.-- A. Hoyos de Castro y F. González García / Identificación y propiedades de un caolín español.-- A. Hoyos de Castro y J. M. Ahumada Buesa / Nota sobre materiales de alfarería.-- F. Pino y J. Acosta Rodríguez / Nota sobre la determinación de hierro (II) en silicatos y rocas.-- Isidoro Asensio Amor / Estudio comparativo de métodos de análisis granulométricos de suelos.-- Luis Cavanillas Rodríguez / Estudios de transpiración vegetal (experiencías en Iisímetros con cultivos de maíz).--José Mª Rodríguez de la Borbolla y Alcalá / La influencia del cloro sobre las plantas.-- J. A. Jiménez Salas / La mecánica del suelo, una nueva rama de la Edafología (II).-- Charles Thom / Control de la población microbiana del suelo.-- Libros publicados.-- Reseña[Volumen 2] Manuel Carlos Alvarez Querol / Variables que influyen sobre la razón molecular sílice/alúmina en los suelos graníticos españoles.-- Ángel Hoyos de Castro / Contribución al estudio de los suelos silícicos españoles.-- Arturo Caballero López / Estudios fisiológicos relacionados con las fitohormonas en Sterubergia Lutea Gawl. et Ker.-- Charles Thom / The Penicillia. Molds men meet everyday (Los Penicillium, mohos que vemos todos los días).-- José Mª Sierra de la Guerra / ¿Edafología o Geonomía?.-- Reseña[Volumen 3] Vicente Aleixandre Ferrandis / Caracterización de algunas arcillas españolas por cambio de bases y curvas de deshidratación.-- José Mª Albareda Herrera y Cruz Rodríguez Muñoz.-Fenómenos de ordenación y reoanisotropía de arcillas.-- Fernando Burriel Martí y Valentín Hernando Fernández / El fósforo en los suelos españoles : I. Contribución a la determinación colorimétrica del fósforo.-- Florencio Bustinza Lachiondo y Arturo Caballero López / Sobre el empleo de un excipiente hidrosoluble en las técnicas de aplicación de fitohormonas.-- Ernesto Vieitez Cortizo y José L. Blanco / Relaciones entre la condición genética del maíz y las características biométricas de su polen (Trabajo preliminar).-- José Mª Albareda Herrera y Vicente Aleixandre Ferrandis / Sobre la aditividad en las deshidrataciones de mezclas de los minerales de arcilla.-- Libros publicados.--ReseñaPeer reviewe

Asteroseismology of the DOV Star PG 1159-035 with the Whole Earth Telescope

We report the results from 264.1 hr of nearly continuous time-series photometry on the pulsating pre-white dwarf star (DOV) PG 1159-035. The high-resolution power spectrum of this data set is dominated by power in the range from roughly 1000 to 2600 μHz (1000 s to 385 s periods). This power is completely resolved into 125 individual frequencies; we have identified 101 of them with specific, quantized pulsation modes, and the rest are completely consistent with such modal assignment. The luminosity variations are therefore certainly the result of g-mode pulsations. Although the amplitudes of some of the peaks exhibit significant variations on time scales of a year or so, the underlying frequency structure of the pulsations is stable over much longer intervals. With the help of existing linear theory we use these identifications to determine, or strongly constrain, many of the fundamental physical parameters describing this star. We find its mass to be 0.586 M⊙, its rotation period 1.38 days, its magnetic field less than 6000 G, its pulsation and rotation axes to be aligned, and its outer layers to be compositionally stratified. With straightforward extensions of existing theory it may be possible to determine uniquely from this data set all of the parameters necessary to construct a quantitative model of its interior. These observations also reveal several interesting phenomena that challenge the current theory of nonradial pulsations, and may require substantial new developments to describe them

Asteroseismology of the dov star PG 1159-035 with the Whole Earth Telescope

We report the results from 264.1 hr of nearly continuous time-series photometry on the pulsating pre-white dwarf star (DOV) PG 1159-035. The high-resolution power spectrum of this data set is dominated by power in the range from roughly 1000 to 2600 μHz (1000 s to 385 s periods). This power is completely resolved into 125 individual frequencies; we have identified 101 of them with specific, quantized pulsation modes, and the rest are completely consistent with such moda! assignment. The luminosity variations are therefore certainly the result of g-mode pulsations. Although the amplitudes of some of the peaks exhibit significant variations on time scales of a year or so, the underlying frequency structure of the pulsations is stable over much longer intervals. With the help of existing linear theory we use these identifications to determine, or strongly constrain, many of the fundamental physical parameters describing this star. We find its mass to be 0.586 Mʘ , its rotation period 1.38 days, its magnetic field less than 6000 G, its pulsation and rotation axes to be aligned, and its outer layers to be compositionally stratified. With straightforward extensions of existing theory it may be pos­ sible to determine uniquely from this data set ali of the parameters necessary to construct a quantitative model of its interior. These observations also reveal severa! interesting phenomena that challenge the current theory of nonradial pulsations, and may require substantial new developments to describe them