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Theoretical Zero Age Main Sequences revisited

V. Castellani·S. Degl' Innocenti·M. Marconi
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Abstract

Zero Age Main Sequence (ZAMS) models with updated physical inputs are presented for selected assumptions about the chemical composition, covering the ranges 0.6 < M/Mo < 1.2, 0.0001 < Z < 0.04, 0.23 < Y < 0.34.The HR diagram location of the ZAMS as a function of Y and Z is discussed both in the theoretical and in the observational HR diagrams, showing that the V magnitude presents an increased dependence on Z to be taken into account when discussing observational evidences. Analytical relations quantifying both these dependences are derived. Implications for the galactic helium to heavier elements enrichment are finally discussed.

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V. Castellani, S. Degl' Innocenti, M. Marconi. 1999-08-26. Theoretical Zero Age Main Sequences revisited. https://arxiv.org/abs/astro-ph/9908291

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