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Full-Text Articles in Physical Sciences and Mathematics

Experimental Results Of Neutron Fluence Outside An Iron Shield In The Forward Direction, M. M.C. Torres, A. J. Elwyn, D. Fein, E. James, K. Johns, W. Davis, D. P. Ciampa, E. Mierkiewicz Sep 1996

Experimental Results Of Neutron Fluence Outside An Iron Shield In The Forward Direction, M. M.C. Torres, A. J. Elwyn, D. Fein, E. James, K. Johns, W. Davis, D. P. Ciampa, E. Mierkiewicz

Publications

This work represents the first systematic study at a high energy accelerator of the depth dependence of neutron fluence in longitudinal shielding.


The Metallicity Dependence Of The Stellar Luminosity And Initial Mass Functions: Hst Observations Of Open And Globular Clusters, Ted Von Hippel, Gerard Gilmore, Nial R. Tanvir, David Robinson, Derek H.P. Jones Jul 1996

The Metallicity Dependence Of The Stellar Luminosity And Initial Mass Functions: Hst Observations Of Open And Globular Clusters, Ted Von Hippel, Gerard Gilmore, Nial R. Tanvir, David Robinson, Derek H.P. Jones

Publications

Using HST and the WFPC2 we have acquired very deep V- and I-band photometry of stars in NGC 2420 and NGC 2477 to study cluster luminosity functions at approximately solar metallicity. We have determined these cluster luminosity functions down to MI = 10.5 (0.2 M⊙) and find that the luminosity function of NGC 2420 turns over at MI ≈ 9.0, and possibly stops altogether by MI ≈ 9.5. The luminosity function of NGC 2477 may flatten at MI ≥ 9.5. We compare our open cluster luminosity functions to the solar neighborhood field star luminosity function of Kroupa, Tout \& Gilmore …


Main Sequence Masses And Radii From Gravitational Redshifts, Ted Von Hippel Feb 1996

Main Sequence Masses And Radii From Gravitational Redshifts, Ted Von Hippel

Publications

Modern instrumentation makes it possible to measure the mass to radius ratio for main sequence stars in open clusters from gravitational redshifts. For stars where independent information is available for either the mass or the radius, this application of general relativity directly determines the other quantity. Applicable examples are: 1) measuring the radii of solar metallicity main sequence stars for which the mass - luminosity relation is well known, 2) measuring the radii for stars where model atmospheres can be used to determine the surface gravity (the mass to radius squared ratio), 3) refining the mass - radius relation for …


The Application Of Artificial Neural Networks To Stellar Classification, Coryn A. L. Jones, Mike Irwin, Ted Von Hippel Jan 1996

The Application Of Artificial Neural Networks To Stellar Classification, Coryn A. L. Jones, Mike Irwin, Ted Von Hippel

Publications

We are working on a project to automate the multi-parameter classification of stellar spectra using Principal Components Analysis (PCA) and Artificial Neural Networks. We present here the usefulness of PCA as a form of spectral data compression, and our results to date of classification on the MK system.