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Full-Text Articles in Physical Sciences and Mathematics
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
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
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 …