8,369 research outputs found
The Metallicities of Stars With and Without Transiting Planets
Host star metallicities have been used to infer observational constraints on
planet formation throughout the history of the exoplanet field. The giant
planet metallicity correlation has now been widely accepted, but questions
remain as to whether the metallicity correlation extends to the small
terrestrial-sized planets. Here, we report metallicities for a sample of 518
stars in the Kepler field that have no detected transiting planets and compare
their metallicity distribution to a sample of stars that hosts small planets
(Rp < 1.7 R_Earth). Importantly, both samples have been analyzed in a
homogeneous manner using the same set of tools (Stellar Parameters
Classification tool; SPC). We find the average metallicity of the sample of
stars without detected transiting planets to be [m/H]_SNTP,dwarf = -0.02 +-
0.02 dex and the sample of stars hosting small planets to be [m/H]_STP = -0.02
+- 0.02 dex. The average metallicities of the two samples are indistinguishable
within the uncertainties, and the two-sample Kolmogorov-Smirnov test yields a
p-value of 0.68 (0.41 sigma), indicating a failure to reject the null
hypothesis that the two samples are drawn from the same parent population. We
conclude that the homogeneous analysis of the data presented here support the
hypothesis that stars hosting small planets have a metallicity similar to stars
with no known transiting planets in the same area of the sky.Comment: Accepted for publication in Ap
A NASTRAN model of a large flexible swing-wing bomber. Volume 3: NASTRAN model development-wing structure
The NASTRAN model plan for the wing structure was expanded in detail to generate the NASTRAN model for this substructure. The grid point coordinates were coded for each element. The material properties and sizing data for each element were specified. The wing substructure model was thoroughly checked out for continuity, connectivity, and constraints. This substructure was processed for structural influence coefficients (SIC) point loadings and the deflections were compared to those computed for the aircraft detail model. Finally, a demonstration and validation processing of this substructure was accomplished using the NASTRAN finite element program. The bulk data deck, stiffness matrices, and SIC output data were delivered
A NASTRAN model of a large flexible swing-wing bomber. Volume 5: NASTRAN model development-fairing structure
The NASTRAN model plan for the fairing structure was expanded in detail to generate the NASTRAN model of this substructure. The grid point coordinates, element definitions, material properties, and sizing data for each element were specified. The fairing model was thoroughly checked out for continuity, connectivity, and constraints. The substructure was processed for structural influence coefficients (SIC) point loadings to determine the deflection characteristics of the fairing model. Finally, a demonstration and validation processing of this substructure was accomplished using the NASTRAN finite element program. The bulk data deck, stiffness matrices, and SIC output data were delivered
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