Getting SMARTS on Novae: Highlights of the Early Evolution of Nova V475 Sct     

Guy S. Stringfellow  Frederich M. Walter 《Astrophysics and Space Science》2006,304(1-4):401-403

There is a disconcerting global trend of retiring telescopes of modest aperture, supplanting them instead with fewer expensive telescopes of quite large aperture. As a consequence, the available time and feasibility of following transient objects in astrophysics is diminishing. We show the utility of having a suite of small to moderate aperture telescopes capable of conducting imaging and spectroscopic observations in a service queue mode. The example we provide is the high-cadence early observations of the classical nova V475 Scuti (2003) carried out with the SMARTS suite of telescopes located at CTIO.  相似文献   

Solar wind-magnetosphere interaction as simulated by a 3-D em particle code     

Ken-Ichi Nishikawa  Torsten Neubert  Oscar Buneman 《Astrophysics and Space Science》1995,227(1-2):265-276

We have studied the solar wind-magnetosphere interaction using a 3-D electromagnetic particle code. The results for an unmagnetized solar wind plasma streaming past a dipole magnetic field show the formation of a magnetopause and a magnetotail, the penetration of energetic particles into cusps and radiation belt and dawn-dusk asymmetries. The effects of interplanetary magnetic field (IMF) have been investigated in a similar way as done by MHD simulations. The simulation results with a southward IMF show the shrunk magnetosphere with great particle entry into the cusps and nightside magnetosphere. This is a signature of a magnetic reconnection at the dayside magnetopause. After a quasi-stable state is established with an unmagnetized solar wind we switched on a solar wind with an northward IMF. In this case the significant changes take place in the magnetotail. The waving motion was seen in the magnetotail and its length was shortened. This phenomena are consistent with the reconnections which occur at the high latitude magnetopause. In our simulations kinetic effects will determine the self-consistent anomalous resistivity in the magnetopause that causes reconnections.Deceased January 24, 1993; R. Bunemanet al. 1993.  相似文献   

Refined conceptualization of TOPMODEL for shallow subsurface flows     

M. Todd Walter  Tammo S. Steenhuis  Vishal K. Mehta  Dominique Thongs  Mark Zion  Elliot Schneiderman 《水文研究》2002,16(10):2041-2046

The TOPMODEL framework was used to derive expressions that account for saturated and unsaturated flow through shallow soil on a hillslope. The resulting equations were the basis for a shallow‐soil TOPMODEL (STOPMODEL). The common TOPMODEL theory implicitly assumes a water table below the entire watershed and this does not conceptually apply to systems hydrologically controlled by shallow interflow of perched groundwater. STOPMODEL provides an approach for extending TOPMODEL's conceptualization to apply to shallow, interflow‐driven watersheds by using soil moisture deficit instead of water table depth as the state variable. Deriving STOPMODEL by using a hydraulic conductivity function that changes exponentially with soil moisture content results in equations that look very similar to those commonly associated with TOPMODEL. This alternative way of conceptualizing TOPMODEL makes the modelling approach available to researchers, planners, and engineers who work in areas where TOPMODEL was previously believed to be unsuited, such as the New York City Watershed in the Catskills region of New York State. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

The Albian to Maastrichtian of Southern Sweden and Bornholm, Denmark: a review     

Walter Kegel Christensen 《Cretaceous Research》1984,5(4):313-327

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Note on the Paper of A. H. Cook, "The External Gravity Field of a Rotating Spheroid to the order of e³"     

Walter D. Lambert 《Geophysical Journal International》1960,3(3):360-366

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The determination of weakly and strongly bound copper,lead and cadmium in oslofjord samples     

Steinar K. Nilsen  Walter Lund 《Marine Chemistry》1982,11(3):223-233

Weakly and strongly bound copper, lead and cadmium have been determined in the dissolved and particulate fractions of water samples from Oslofjord. The differentiation was made possible by using different sequences of filtration, acidification and digestion. The quantitative measurements were done by differential pulse anodic stripping voltammetry. Lead was found to be associated mostly with particulate matter, while cadmium was present only in the dissolved fraction. A strong digestion was needed for the determination of total metal. The advantage of pretreating sample bottles and filters with a conditioning solution is illustrated.  相似文献   

Site Correction for Long Period Seismometers, Tiltmeters and Strainmeters     

Geoffrey King  Walter Zurn  Russ Evans  Dieter Emter 《Geophysical Journal International》1976,44(2):405-411

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Late Cretaceous geomagnetic polarity sequence: detailed rock and palaeomagnetic studies of the Scaglia Rossa limestone at Gubbio, Italy     

William Lowrie  Walter Alvarez 《Geophysical Journal International》1977,51(3):561-581

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Compression of ephemerides     

Deprit  André  Poplarchek  Walter  Deprit-Bartholomé  Andrée 《Celestial Mechanics and Dynamical Astronomy》1975,11(1):53-58

Approximations in the normL ₁ by Chebyshev polynomials are generated to represent astronomical ephemerides over large intervals of time.  相似文献   

Association of spherical and ellipsoidal gravity coefficients of the Earth's potential     

Hans G. Walter 《Celestial Mechanics and Dynamical Astronomy》1970,2(3):389-397

A comparison is drawn between the expansion of the potential in spherical harmonics on the one hand and in ellipsoidal harmonics on the other, with the objective of associating the spherical and ellipsoidal gravity coefficients of the Earth's potential.For this purpose the properties of orthogonality of the Lamé functions of the first kind have been tailored to this subject of investigation and become instrumental in establishing the mathematical expressions which relate the two classes of gravity coefficients to each other. In deriving the elements of the transition matrices elliptic integrals have been encountered whose reduction to the three kinds of canonical elliptic integrals is discussed.Presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, August 17–23, 1969.  相似文献