59 research outputs found
Binary Star Light Curve and Model of TYC 3670-588-1 from Professional-Amateur Collaboration, A
We present the orbital light curve and model system parameters of a newly discovered eclipsing binary star in the constellation of Perseus. Our professional-amateur astronomy collaboration between Arkansas Tech University (ATU), the Central Arkansas Astronomy Society (CAAS) and Whispering Pine Observatory, produced photometry in two wavelengths (Johnson V and R) in order to model the system for fundamental parameters with a binary modeling code. We determined that this binary system contains two F-type stars orbiting each other with a short orbital period and having the following characteristics for the two components: mass ratio (q ~ 0.92), temperatures (T1~ 7170 K, T2~ 7350 K), sizes (R1~ 1.7 R sun, R2~2.4 R sun), orbital inclination (i ~ 77o), and stellar separation (a ~ 8.3 R sun). The ephemeris for physical observations and primary mid-eclipse orbital phasing from the period in days is (HJD 2456488.885 + 1.292467 x N)
Effectiveness of mitigation measures to reduce interactions between commercial fishing gear and whales
Effectiveness of mitigation measures to reduce interactions between commercial fishing gear and whales.
Objectives:
1. Start to collect additional information required to determine the spatial and temporal extent of migrating whales and how this overlaps with commercial fishing gear.
2. Examine the effectiveness of potential gear modifications to the float rigs of fishing pots/traps to reduce their likelihood of entangling whales
SWIFT observations of TeV BL Lac objects
Context: We present the results of a set of observations of nine TeV detected
BL Lac objects performed by the XRT and UVOT detectors on board the Swift
satellite between March and December 2005. Aims: We are mainly interested in
measuring the spectral parameters, and particularly the intrinsic curvature in
the X-ray band. Methods: We perform X-ray spectral analysis of observed BL Lac
TeV objects using either a log-parabolic or a simple power-law model . Results:
We found that many of the objects in our sample do show significant spectral
curvature, whereas those having the peak of the spectral energies distribution
at energies lower than ~0.1 keV show power law spectra. In these cases,
however, the statistics are generally low thus preventing a good estimate of
the curvature. Simultaneous UVOT observations are important to verify how X-ray
spectra can be extrapolated at lower frequencies and to search for multiple
emission components. Conclusions: The results of our analysis are useful for
the study of possible signatures of statistical acceleration processes
predicting intrinsically curved spectra and for modelling the SED of BL
Lacertae objects up to TeV energies where a corresponding curvature is likely
to be present.Comment: 10 pages, 7 figures. Accepted for publication in the Astronomy and
Astrophysic
Associative and Spatial Relationships in Thesaurus-based Retrieval
The OASIS (Ontologically Augmented Spatial Information System) project explores terminology systems for thematic and spatial access in digital library applications. A prototype implementation uses data from the Royal Commission on the Ancient and Historical Monuments of Scotland, together with the Getty AAT and TGN thesauri. This paper describes its integrated spatial and thematic schema and discusses novel approaches to the application of thesauri in spatial and thematic semantic distance measures. Semantic distance measures can underpin interactive and automatic query expansion techniques by ranking lists of candidate terms. We first illustrate how hierarchical spatial relationships can be used to provide more flexible retrieval for queries incorporating place names in applications employing online gazetteers and geographical thesauri. We then employ a set of experimental scenarios to investigate key issues affecting use of the associative (RT) thesaurus relationships in semantic distance measures. Previous work has noted the potential of RTs in thesaurus search aids but the problem of increased noise in result sets has been emphasised. Specialising RTs allows the possibility of dynamically linking RT type to query context. Results presented in this paper demonstrate the potential for filtering on the context of the RT link and on subtypes of RT relationships
Physics of Solar Prominences: II - Magnetic Structure and Dynamics
Observations and models of solar prominences are reviewed. We focus on
non-eruptive prominences, and describe recent progress in four areas of
prominence research: (1) magnetic structure deduced from observations and
models, (2) the dynamics of prominence plasmas (formation and flows), (3)
Magneto-hydrodynamic (MHD) waves in prominences and (4) the formation and
large-scale patterns of the filament channels in which prominences are located.
Finally, several outstanding issues in prominence research are discussed, along
with observations and models required to resolve them.Comment: 75 pages, 31 pictures, review pape
The National Criticality Experiments Research Center and its role in support of advanced reactor design
The National Criticality Experiments Research Center (NCERC) located at the Nevada National Security Site (NNSS) in the Device Assembly Facility (DAF) and operated by Los Alamos National Laboratory (LANL) is the only general purpose critical experiments facility in the United States. Experiments from subcritical to critical and above prompt critical are carried out at NCERC on a regular basis. In recent years, NCERC has become more involved in experiments related to nuclear energy, including the Kilopower/KRUSTY demonstration and the recent Hypatia experiment. Multiple nuclear energy related projects are currently ongoing at NCERC. This paper discusses NCERC’s role in advanced reactor design and how that role may change in the future
Problems of the Infrared Solar Spectrum
Author Institution: The Observatory of the University of MichiganPresentations without an abstract printed in the proceedings do not have an abstract (image or text) in the Knowledge Bank record
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