Abstract Observational data on 86 pre-main sequence double-lined spectroscopic binaries (SB2s) were collected. Among them there are Herbig Ae/Be stars, T Tauri stars, and red dwarfs. Distributions of pre-main sequence (young) stars by masses and mass ratios of the components have been constructed, both observed and corrected for observational selection effects. The mass distributions of the components are approximated with a power law dN ~ M–Γ(<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(d\log M\)</EquationSource>  </InlineEquation>), the exponent of which is <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({{\Gamma }} = 1.52 \pm 0.44\)</EquationSource>  </InlineEquation> for the observed distribution and <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({{\Gamma }} = 0.94 \pm 0.19\)</EquationSource>  </InlineEquation> for the distribution corrected for the effects of observational selection on an interval from the distribution maximum to the highest mass value, which is close to the Salpeter mass function. The most probable values of masses are Mprob = (0.76 ± 0.05) <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({{M}_{ \odot }}\)</EquationSource>  </InlineEquation> and Mprob = (0.93 ± 0.02) <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\({{M}_{ \odot }}\)</EquationSource>  </InlineEquation>, respectively. Both the observed and the corrected for the effects of observational selection distributions of young SB2 systems in terms of the mass ratio have a maximum in the interval q = 0.9–1.0. In systems with <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(P < {{10}^{{\text{d}}}}\)</EquationSource>  </InlineEquation> this maximum is more pronounced, and there is a secondary maximum at q = 0.5–0.6. For young SB2 stars with <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(P > {{10}^{{\text{d}}}}\)</EquationSource>  </InlineEquation> the mass-ratio distribution is flatter.

The Distribution of Young Spectroscopic Binary Stars by Masses and by Mass Ratio of the Components Corrected for Observational Selection Effects

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2025年11月1日

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O. V. Eretnova,
G. N. Dremova,
D. V. Tarasova

摘要

Abstract

Observational data on 86 pre-main sequence double-lined spectroscopic binaries (SB2s) were collected. Among them there are Herbig Ae/Be stars, T Tauri stars, and red dwarfs. Distributions of pre-main sequence (young) stars by masses and mass ratios of the components have been constructed, both observed and corrected for observational selection effects. The mass distributions of the components are approximated with a power law dN ~ M^–Γ( \(d\log M\) ), the exponent of which is \({{\Gamma }} = 1.52 \pm 0.44\) for the observed distribution and \({{\Gamma }} = 0.94 \pm 0.19\) for the distribution corrected for the effects of observational selection on an interval from the distribution maximum to the highest mass value, which is close to the Salpeter mass function. The most probable values of masses are M_prob = (0.76 ± 0.05) \({{M}_{ \odot }}\) and M_prob = (0.93 ± 0.02) \({{M}_{ \odot }}\) , respectively. Both the observed and the corrected for the effects of observational selection distributions of young SB2 systems in terms of the mass ratio have a maximum in the interval q = 0.9–1.0. In systems with \(P < {{10}^{{\text{d}}}}\) this maximum is more pronounced, and there is a secondary maximum at q = 0.5–0.6. For young SB2 stars with \(P > {{10}^{{\text{d}}}}\) the mass-ratio distribution is flatter.