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1,2-HOIQO--A highly versatile 1,2-HOPO analog (open access)

1,2-HOIQO--A highly versatile 1,2-HOPO analog

A cyclic, bidentate hydroxamic acid binding unit based on an isoquinoline scaffold has been utilized for the synthesis of a hexadentate tripodal ligand based on the TREN backbone. This prototype for a new class of multidentate chelators forms mononuclear iron(III) complexes and one-dimensional coordination polymers with lanthanide(III) cations. The latter has been determined by single crystal X-ray analysis of the cerium species. The solid state structure in the monoclinic space group P2{sub 1}/c (C{sub 36}H{sub 34}CeN{sub 7}O{sub 11}, a = 12.341(2){angstrom}, b = 26.649(4){angstrom}, c = 10.621(2){angstrom}, {alpha} = {gamma} = 90{sup o}, {beta} = 96.753(3){sup o}, V = 3468.6(9) {angstrom}{sup 3}, Z = 4) exhibits a trigonal-dodecahedral environment around the cerium cation. The proof of concept for the versatility of the new scaffold has been shown by the modification of the crucial precursor 3-carboxyiso-coumarin through electrophilic aromatic substitutions to yield the corresponding chlorosulfonated and nitrated analogs.
Date: August 7, 2006
Creator: Seitz, Michael; Pluth, Michael D. & Raymond, Kenneth N.
System: The UNT Digital Library
A 3D Model for Ion Beam Formation and Transport Simulation (open access)

A 3D Model for Ion Beam Formation and Transport Simulation

In this paper, we present a three-dimensional model forself-consistently modeling ion beam formation from plasma ion sources andtransporting in low energy beam transport systems. A multi-sectionoverlapped computational domain has been used to break the originaltransport system into a number of weakly coupled subsystems. Within eachsubsystem, macro-particle tracking is used to obtain the charge densitydistribution in this subdomain. The three-dimensional Poisson equation issolved within the subdomain after each particle tracking to obtain theself-consistent space-charge forces and the particle tracking is repeateduntil the solution converges. Two new Poisson solvers based on acombination of the spectral method and the finite difference multigridmethod have been developed to solve the Poisson equation in cylindricalcoordinates for the straight beam transport section and in Frenet-Serretcoordinates for the bending magnet section. This model can have importantapplication in design and optimization of the low energy beam line opticsof the proposed Rare Isotope Accelerator (RIA) front end.
Date: February 7, 2006
Creator: Qiang, J.; Todd, D. & Leitner, D.
System: The UNT Digital Library
Abstract Proceedings Signal and Imaging Sciences Workshop CASIS Workshop 2006 (open access)

Abstract Proceedings Signal and Imaging Sciences Workshop CASIS Workshop 2006

These abstracts cover the following topics: (1) Analysis of massive datasets; (2) Nondestructive evaluation; (3) Imaging methodology; (4) NIF optics inspection; (5) Model-based signal processing and estimation; and (6) Image processing and analysis.
Date: November 7, 2006
Creator: Roberts, R
System: The UNT Digital Library
Accurate Astrometry and Photometry of Saturated and Coronagraphic Point Spread Functions (open access)

Accurate Astrometry and Photometry of Saturated and Coronagraphic Point Spread Functions

For ground-based adaptive optics point source imaging, differential atmospheric refraction and flexure introduce a small drift of the point spread function (PSF) with time, and seeing and sky transmission variations modify the PSF flux. These effects need to be corrected to properly combine the images and obtain optimal signal-to-noise ratios, accurate relative astrometry and photometry of detected companions as well as precise detection limits. Usually, one can easily correct for these effects by using the PSF core, but this is impossible when high dynamic range observing techniques are used, like coronagraphy with a non-transmissive occulting mask, or if the stellar PSF core is saturated. We present a new technique that can solve these issues by using off-axis satellite PSFs produced by a periodic amplitude or phase mask conjugated to a pupil plane. It will be shown that these satellite PSFs track precisely the PSF position, its Strehl ratio and its intensity and can thus be used to register and to flux normalize the PSF. This approach can be easily implemented in existing adaptive optics instruments and should be considered for future extreme adaptive optics coronagraph instruments and in high-contrast imaging space observatories.
Date: February 7, 2006
Creator: Marois, C; Lafreniere, D; Macintosh, B & Doyon, R
System: The UNT Digital Library
Amphotericin B induced interdigitation of apolipoprotein stabilized nanodisk bilayers (open access)

Amphotericin B induced interdigitation of apolipoprotein stabilized nanodisk bilayers

Amphotericin B nanodisks (AMB-ND) are ternary complexes of AMB, phospholipid (PL) and apolipoprotein organized as discrete nanometer scale disk-shaped bilayers. In gel filtration chromatography experiments, empty ND lacking AMB elute as a single population of particles with a molecular weight in the range of 200 kDa. AMB-ND formulated at a 4:1 PL:AMB weight ratio, separated into two peaks. Peak 1 eluted at the position of control ND lacking AMB while the second peak, containing all of the AMB present in the original sample, eluted in the void volume. When ND prepared with increased AMB (1:1 phospholipid:AMB molar ratio) were subjected to gel filtration chromatography, an increased proportion of phospholipid and apolipoprotein were recovered in the void volume with the AMB. Prior to gel filtration the AMB-ND sample could be passed through a 0.22 {micro}m filter without loss of AMB while the voided material was lost. Native gel electrophoresis studies corroborated the gel permeation chromatography data. Far UV circular dichroism analyses revealed that apoA-I associated with AMB-ND denatures at a lower guanidine HCl concentration than apoA-I associated with ND lacking AMB. Atomic force microscopy revealed that AMB induces compression of the ND bilayer thickness consistent with bilayer interdigitation, a phenomenon that …
Date: December 7, 2006
Creator: Nguyen, T; Weers, P M; Sulchek, T; Hoeprich, P D & Ryan, R O
System: The UNT Digital Library
The Application of Global Kinetic Models to HMX Beta-Delta Transition and Cookoff Processes (open access)

The Application of Global Kinetic Models to HMX Beta-Delta Transition and Cookoff Processes

The reduction of the number of reactions in kinetic models for both the HMX beta-delta phase transition and thermal cookoff provides an attractive alternative to traditional multi-stage kinetic models due to reduced calibration effort requirements. In this study, we use the LLNL code ALE3D to provide calibrated kinetic parameters for a two-reaction bidirectional beta-delta HMX phase transition model based on Sandia Instrumented Thermal Ignition (SITI) and Scaled Thermal Explosion (STEX) temperature history curves, and a Prout-Tompkins cookoff model based on One-Dimensional Time to Explosion (ODTX) data. Results show that the two-reaction bidirectional beta-delta transition model presented here agrees as well with STEX and SITI temperature history curves as a reversible four-reaction Arrhenius model, yet requires an order of magnitude less computational effort. In addition, a single-reaction Prout-Tompkins model calibrated to ODTX data provides better agreement with ODTX data than a traditional multi-step Arrhenius model, and can contain up to 90% less chemistry-limited time steps for low-temperature ODTX simulations. Manual calibration methods for the Prout-Tompkins kinetics provide much better agreement with ODTX experimental data than parameters derived from Differential Scanning Calorimetry (DSC) measurements at atmospheric pressure. The predicted surface temperature at explosion for STEX cookoff simulations is a weak function of …
Date: December 7, 2006
Creator: Wemhoff, A. P.; Burnham, A. K. & Nichols, A. L., III
System: The UNT Digital Library
An Approach to Industrial Stormwater Benchmarks: Establishing and Using Site-Specific Threshold Criteria at Lawrence Livermore National Laboratory (open access)

An Approach to Industrial Stormwater Benchmarks: Establishing and Using Site-Specific Threshold Criteria at Lawrence Livermore National Laboratory

Current regulatory schemes use generic or industrial sector specific benchmarks to evaluate the quality of industrial stormwater discharges. While benchmarks can be a useful tool for facility stormwater managers in evaluating the quality stormwater runoff, benchmarks typically do not take into account site-specific conditions, such as: soil chemistry, atmospheric deposition, seasonal changes in water source, and upstream land use. Failing to account for these factors may lead to unnecessary costs to trace a source of natural variation, or potentially missing a significant local water quality problem. Site-specific water quality thresholds, established upon the statistical evaluation of historic data take into account these factors, are a better tool for the direct evaluation of runoff quality, and a more cost-effective trigger to investigate anomalous results. Lawrence Livermore National Laboratory (LLNL), a federal facility, established stormwater monitoring programs to comply with the requirements of the industrial stormwater permit and Department of Energy orders, which require the evaluation of the impact of effluent discharges on the environment. LLNL recognized the need to create a tool to evaluate and manage stormwater quality that would allow analysts to identify trends in stormwater quality and recognize anomalous results so that trace-back and corrective actions could be initiated. …
Date: September 7, 2006
Creator: Campbell, C G & Mathews, S
System: The UNT Digital Library
Background Modelling in Very-High-Energy Gamma-Ray Astronomy (open access)

Background Modelling in Very-High-Energy Gamma-Ray Astronomy

Ground based Cherenkov telescope systems measure astrophysical {gamma}-ray emission against a background of cosmic-ray induced air showers. The subtraction of this background is a major challenge for the extraction of spectra and morphology of {gamma}-ray sources. The unprecedented sensitivity of the new generation of ground based very-high-energy {gamma}-ray experiments such as H.E.S.S. has lead to the discovery of many previously unknown extended sources. The analysis of such sources requires a range of different background modeling techniques. Here we describe some of the techniques that have been applied to data from the H.E.S.S. instrument and compare their performance. Each background model is introduced and discussed in terms of suitability for image generation or spectral analysis and possible caveats are mentioned. We show that there is not a single multi-purpose model, different models are appropriate for different tasks. To keep systematic uncertainties under control it is important to apply several models to the same data set and compare the results.
Date: November 7, 2006
Creator: Berge, David; /Heidelberg, Max Planck Inst. /CERN; Funk, S.; /Heidelberg, Max Planck Inst. /KIPAC, Menlo Park; Hinton, J. & /Heidelberg, Max Planck Inst. /Heidelberg Observ. /Leeds U.
System: The UNT Digital Library
Berkeley Accelerator Space Effects (BASE) Light Ion FacilityUpgrade (open access)

Berkeley Accelerator Space Effects (BASE) Light Ion FacilityUpgrade

The BASE Light Ion Facility upgrades have been completed. All proton beams are now delivered to Cave 4A. New control software, a larger diameter beam window, and improved quality assurance measures have been added.
Date: July 7, 2006
Creator: Johnson, Michael B.; McMahan, Margaret A.; Gimpel, Thomas L. & Tiffany, William S.
System: The UNT Digital Library
Damping Wiggler Study at KEK-ATF (open access)

Damping Wiggler Study at KEK-ATF

The effects of damping wiggler magnets have been studied at KEK-ATF damping ring, which is a 1.3 GeV storage ring capable of producing ultra-low emittance electron beams. The fast beam damping is a significant issue for the damping ring. The tuning method with 4 sets of wiggler magnets was investigated for the ultra-low emittance beam. The effect on the beam quality, which is related to the transverse (x and y) and the longitudinal (z and {Delta}p/p), has been measured by the wire scanner, SR monitor, the laser wire, streak camera and the energy spread monitor. We report on the operational condition and the measurement results.
Date: February 7, 2006
Creator: Naito, T.; Hayano, H.; Honda, Y.; Kubo, K.; Kuriki, M.; Kuroda, S. et al.
System: The UNT Digital Library
Design of a combinatorial dna microarray for protein-dnainteraction studies (open access)

Design of a combinatorial dna microarray for protein-dnainteraction studies

Background: Discovery of precise specificity oftranscription factors is an important step on the way to understandingthe complex mechanisms of gene regulation in eukaryotes. Recently,doublestranded protein-binding microarrays were developed as apotentially scalable approach to tackle transcription factor binding siteidentification. Results: Here we present an algorithmic approach toexperimental design of a microarray that allows for testing fullspecificity of a transcription factor binding to all possible DNA bindingsites of a given length, with optimally efficient use of the array. Thisdesign is universal, works for any factor that binds a sequence motif andis not species-specific. Furthermore, simulation results show that dataproduced with the designed arrays is easier to analyze and would resultin more precise identification of binding sites. Conclusion: In thisstudy, we present a design of a double stranded DNA microarray forprotein-DNA interaction studies and show that our algorithm allowsoptimally efficient use of the arrays for this purpose. We believe such adesign will prove useful for transcription factor binding siteidentification and other biological problems.
Date: July 7, 2006
Creator: Mintseris, Julian & Eisen, Michael B.
System: The UNT Digital Library
Development and Implementation of an Ergonomics Program for Research Laboratories (open access)

Development and Implementation of an Ergonomics Program for Research Laboratories

None
Date: March 7, 2006
Creator: Roberts, T.; Yu, E. & Herbert, R.
System: The UNT Digital Library
The Dynamics of an Isolated Plasma Filament at the Edge of a Toroidal Device (open access)

The Dynamics of an Isolated Plasma Filament at the Edge of a Toroidal Device

None
Date: September 7, 2006
Creator: Ryutov, D. D.
System: The UNT Digital Library
Electronic Excitations and Metal-Insulator Transition inPoly(3-hexylthiophene) Organic Field-Effect Transistors (open access)

Electronic Excitations and Metal-Insulator Transition inPoly(3-hexylthiophene) Organic Field-Effect Transistors

We carry out a comprehensive theoretical and experimentalstudy of charge injection in poly(3-hexylthiophene) (P3HT) to determinethe most likely scenario for metal-insulator transition in this system.Wecalculate the optical-absorption frequencies corresponding to a polaronand a bipolaron lattice in P3HT. We also analyze the electronicexcitations for three possible scenarios under which a first- or asecond-order metal-insulator transition can occur in doped P3HT. Thesetheoretical scenarios are compared with data from infrared absorptionspectroscopy on P3HT thin-film field-effect transistors (FETs). Ourmeasurements and theoretical predictions suggest that charge-inducedlocalized states in P3HT FETs are bipolarons and that the highest dopinglevel achieved in our experiments approaches that required for afirst-order metal-insulator transition.
Date: November 7, 2006
Creator: Sai, N.; Li, Z.Q.; Martin, M.C.; Basov, D.N. & Di Ventra, M.
System: The UNT Digital Library
Enhanced geothermal systems (EGS) using CO2 as working fluid - Anovelapproach for generating renewable energy with simultaneoussequestration of carbon (open access)

Enhanced geothermal systems (EGS) using CO2 as working fluid - Anovelapproach for generating renewable energy with simultaneoussequestration of carbon

Responding to the need to reduce atmospheric emissions of carbon dioxide, Donald Brown (2000) proposed a novel enhanced geothermal systems (EGS) concept that would use CO{sub 2} instead of water as heat transmission fluid, and would achieve geologic sequestration of CO{sub 2} as an ancillary benefit. Following up on his suggestion, we have evaluated thermophysical properties and performed numerical simulations to explore the fluid dynamics and heat transfer issues in an engineered geothermal reservoir that would be operated with CO{sub 2}. We find that CO{sub 2} is superior to water in its ability to mine heat from hot fractured rock. CO{sub 2} also has certain advantages with respect to wellbore hydraulics, where larger compressibility and expansivity as compared to water would increase buoyancy forces and would reduce the parasitic power consumption of the fluid circulation system. While the thermal and hydraulic aspects of a CO{sub 2}-EGS system look promising, major uncertainties remain with regard to chemical interactions between fluids and rocks. An EGS system running on CO{sub 2} has sufficiently attractive features to warrant further investigation.
Date: June 7, 2006
Creator: Pruess, Karsten
System: The UNT Digital Library
Ensuring the Sustainability of Russian Federation National Nuclear Material Accounting System (open access)

Ensuring the Sustainability of Russian Federation National Nuclear Material Accounting System

The Federal Nuclear Material Control and Accounting Information System (FIS) is the national information source on nuclear material accounting of the Russian Federation (RF). RF regulations mandated the creation of a national nuclear material accounting system to be managed by Federal Agency For Atomic Energy (Rosatom), and for the past decade, the FIS has been developed for all organizations required to report to Rosatom. The system represents a successful integration of U.S. financial support and consulting with Russian vision and technical expertise, creating a viable national nuclear material accounting system. This paper discusses crucial elements to ensure Sustainability of the FIS. A long-term plan for operation and maintenance of the information system is critical to a sustainable national accounting system. Plans undertaken throughout the FIS Project lifecycle have supported the necessary elements to ensure success. Through the next two years, long-term planning will be reevaluated and the successful elements and new initiatives will become part of an overall Operations Management Program. FIS resource needs will be managed through prioritization and ranking for each Program element, including: system operation; revising and implementing supporting regulations; establishing monitoring and control mechanisms to ensure validity of the data reported; maintaining and improving communication channels; …
Date: June 7, 2006
Creator: Pitel, V. A.; Kasumova, L. A.; Kushnaryov, M. S. & Babcock, R. A.
System: The UNT Digital Library
Examining MARC Records as Artifacts That Reflect Metadata Utilization Decisions (open access)

Examining MARC Records as Artifacts That Reflect Metadata Utilization Decisions

Article examining MARC records as artifacts that reflect metadata utilization decisions.
Date: August 7, 2006
Creator: Moen, William E.
System: The UNT Digital Library
A FAMILY OF PEROXO-TITANATE MATERIALS TAILORED FOR OPTIMAL STRONTIUM ANDACTINIDE SORPTION (open access)

A FAMILY OF PEROXO-TITANATE MATERIALS TAILORED FOR OPTIMAL STRONTIUM ANDACTINIDE SORPTION

Achieving global optimization of inorganic sorbent efficacy, as well as tailoring sorbent specificity for target sorbates would facilitate increased wide-spread use of these materials in applications such as producing potable water or nuclear waste treatment. Sodium titanates have long been known as sorbents for radionuclides; {sup 90}Sr and transuranic elements in particular. We have developed a related class of materials, which we refer to as peroxo-titanates: these are sodium titanates or hydrous titanates synthesized in the presence of or treated post-synthesis with hydrogen peroxide. Peroxo-titanates show remarkable and universal improved sorption behavior with respect to separation of actinides and strontium from Savannah River Site (SRS) nuclear waste simulants. Enhancement in sorption kinetics can potentially result in as much as an order of magnitude increase in batch processing throughput. Peroxo-titanates have been produced by three different synthetic routes: post-synthesis peroxide-treatment of a commercially produced monosodium titanate, an aqueous-peroxide synthetic route, and an isopropanol-peroxide synthetic route. The peroxo-titanate materials are characteristically yellow to orange, indicating the presence of protonated or hydrated Ti-peroxo species; and the chemical formula can be generally written as H{sub v}Na{sub w}Ti{sub 2}O{sub 5}-(xH{sub 2}O)[yH{sub z}O{sub 2}] where (v+w) = 2, z = 0-2, and total volatile species accounts …
Date: August 7, 2006
Creator: Hobbs, D
System: The UNT Digital Library
A Family of Zinc Finger Proteins Is Required forChromosome-specific Pairing and Synapsis during Meiosis in C.elegans (open access)

A Family of Zinc Finger Proteins Is Required forChromosome-specific Pairing and Synapsis during Meiosis in C.elegans

Homologous chromosome pairing and synapsis are prerequisitefor accurate chromosome segregation during meiosis. Here, we show that afamily of four related C2H2 zinc-finger proteins plays a central role inthese events in C. elegans. These proteins are encoded within a tandemgene cluster. In addition to the X-specific HIM-8 protein, threeadditional paralogs collectively mediate the behavior of the fiveautosomes. Each chromosome relies on a specific member of the family topair and synapse with its homolog. These "ZIM" proteins concentrate atspecial regions called meiotic pairing centers on the correspondingchromosomes. These sites are dispersed along the nuclear envelope duringearly meiotic prophase, suggesting a role analogous to thetelomere-mediated meiotic bouquet in other organisms. To gain insightinto the evolution of these components, wecharacterized homologs in C.briggsae and C. remanei, which revealed changes in copy number of thisgene family within the nematode lineage.
Date: June 7, 2006
Creator: Phillips, Carolyn M. & Dernburg, Abby F.
System: The UNT Digital Library
The galaxy hosts and large-scale environments of short-hard (gamma)-ray bursts (open access)

The galaxy hosts and large-scale environments of short-hard (gamma)-ray bursts

The nature of the progenitors of short duration, hard spectrum, gamma-ray bursts (GRBs) has remained a mystery. Even with the recent localizations of four short-hard GRBs, no transient emission has been found at long wavelengths that directly constrains the progenitor nature. Instead, as was the case in studying the different morphological subclasses of supernovae and the progenitors of long-duration GRBs, we suggest that the progenitors of short bursts can be meaningfully constrained by the environment in which the bursts occur. Here we present the discovery spectra of the galaxies that hosted three short-hard GRBs and the spectrum of a fourth host. The results indicate that these environments, both at the galaxy scale and galaxy-cluster scale, differ substantially from those of long-soft GRBs. The spatial offset of three bursts from old and massive galaxy hosts strongly favors an origin from the merger of compact stellar remnants, such as double neutron stars or a neutron-star black hole binary. The star-forming host of another GRB provides confirmation that, like supernovae of Type Ia, the progenitors of short-hard bursts are created in all galaxy types. This indicates a class of progenitors with a wide distribution of delay times between formation and explosion.
Date: April 7, 2006
Creator: Prochaska, J. X.; Bloom, J. S.; Chen, H.; Foley, R. J.; Perley, D. A.; Ramirez-Ruiz, E. et al.
System: The UNT Digital Library
Gamow-Teller Strength in the A=14 Multiplet: A Challenge to the Shell Model (open access)

Gamow-Teller Strength in the A=14 Multiplet: A Challenge to the Shell Model

A new experimental approach to the famous problem of the anomalously slow Gamow-Teller (GT) transitions in the {beta} decay of the A = 14 multiplet is presented. The GT strength distributions to excited states in {sup 14}C and {sup 14}O was studied in high-resolution (d,{sup 2}He) and ({sup 3}He,t) charge-exchange reactions on {sup 14}N. No-core shell-model (NCSM) calculations capable of reproducing the suppression of the {beta} decays predict a selective excitation of J{sup {pi}} = 2{sup +} states. The experimental confirmation represents a validation of the assumptions about the underlying structure of the {sup 14}N ground state wave function. However, the fragmentation of the GT strength over three 2{sup +} final states remains a fundamental issue not explained by the present NCSM using a 6 {h_bar}{omega} model space, suggesting possibly the need to include cluster structure in these light nuclei in a consistent way.
Date: August 7, 2006
Creator: Negret, A.; Adachi, T.; Barrett, B. R.; Baumer, C.; den Berg, A. V.; Berg, G. et al.
System: The UNT Digital Library
Generalized x-ray scattering cross section from non-equilibrium solids and plasmas (open access)

Generalized x-ray scattering cross section from non-equilibrium solids and plasmas

We propose a modified x-ray form factor that describes the scattering cross section in warm dense matter valid for both the plasma and the solid (crystalline) state. Our model accounts for the effect of lattice correlations on the electron-electron dynamic structure, as well as provides a smooth transition between the solid and the plasma scattering cross sections. In addition, we generalize the expression of the dynamic structure in the case of a two-temperature system (with different electron and ion temperatures). This work provides a unified description of the x-ray scattering processes in warm and dense matter, as the one encountered in inertial confinement fusion, laboratory astrophysics, material science, and high-energy density physics and it can be used to verify temperature relaxation mechanisms in such environments.
Date: February 7, 2006
Creator: Gregori, G; Glenzer, S H & Landen, O L
System: The UNT Digital Library
GLAST: Physics Goals And Instrument Status (open access)

GLAST: Physics Goals And Instrument Status

The Gamma-ray Large Area Space Telescope (GLAST) is a space-based observatory scheduled to launch in October 2007 with two instruments: (1) the GLAST Burst Monitor (GBM), sensitive to photon energies between 8 keV and 25 MeV and optimized to detect gamma-ray bursts, and (2) the Large Area Telescope (LAT), sensitive to gamma rays between 20 MeV and 300 GeV and designed to survey the gamma-ray sky with unprecedented sensitivity. We describe the LAT and the GBM. We then focus on the LAT's capabilities for studying active galactic nuclei.
Date: November 7, 2006
Creator: Carson, Jennifer E.
System: The UNT Digital Library
GQ Lup Ab Visible & Near-Infrared Photometric Analysis (open access)

GQ Lup Ab Visible & Near-Infrared Photometric Analysis

We have re-analyzed archival HST R and I band images and Subaru CH{sub 4}, H, Ks and L{prime} data of the recently discovered planetary mass companion (PMC) GQ Lup Ab. With these we produce the first R and I band photometry of the companion and fit a radius and effective temperature using detailed model atmospheres. We find an effective temperature of 2338 {+-} 100K, and a radius of 0.37 {+-} 0.05R{sub {circle_dot}} and luminosity of log(L/L{sub {circle_dot}}) = -2.43 {+-} 0.07 (at 140pc). Since we fit wavelengths that span most of the emitted radiation from GQ Lup this luminosity estimate is robust, with uncertainty dominated by the distance uncertainty. The radius obtained for 140pc (0.37R{sub {circle_dot}}) is significantly larger than the one originally derived. The mass of the object is much more model-dependent than the radiative properties, but for the GAIA dusty models we find a mass between 9-20 M{sub Jup}, in the range of the brown dwarf and PMC deuterium burning boundary. Assuming a distance of 140pc, observations fit to 1{sigma} the Baraffe evolution model for a {approx} 15 M{sub Jup} brown dwarf. Additionally, the F606W photometric band is significantly overluminous compared to model predictions. Such overluminosity could be …
Date: August 7, 2006
Creator: Marois, C; Macintosh, B & Barman, T
System: The UNT Digital Library