Abstract

view Abstract Citations (37) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radiative Accelerations on Iron Using Opacity Project Data Alecian, G. ; Michaud, G. ; Tully, J. Abstract Radiative accelerations have been calculated in detail for iron in main-sequence models with T(eff) = 6700, 8000, and 10,000 K and log g = 4.0 and 4.3 and a number of Fe abundances. Atomic data for Fe IX to Fe XVII were taken from the Opacity Project, and this allowed us to calculate the accelerations over an important fraction of the envelope and to calibrate formulae that were obtained earlier using data from the first few states of ionization. We have derived approximate formulas that allow our results to be used in stellar evolution calculations. From a comparison of radiative acceleration and gravity, one may conclude that only small Fe abundance anomalies are to be expected in those stars with T(eff) = 6700 K where atomic diffusion is important. For stars with lower effective temperatures, only small underabundances are to be expected. However, in hotter stars, large Fe overabundances are expected in part of the envelope. These would appear at the same time as He underabundances. Iron could then completely dominate the opacity over part of the envelope. Only detailed evolutionary calculations, with the simultaneous inclusion of Fe and He diffusion, will determine where the Fe overabundances appear and how large they are. Publication: The Astrophysical Journal Pub Date: July 1993 DOI: 10.1086/172892 Bibcode: 1993ApJ...411..882A Keywords: Acceleration (Physics); Iron; Main Sequence Stars; Opacity; Radiation Effects; Stellar Evolution; Heavy Elements; Stellar Interiors; Stellar Structure; Stellar Temperature; Astrophysics; DIFFUSION; ATOMIC DATA; STARS: ABUNDANCES; STARS: INTERIORS full text sources ADS |

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