The Metallicity of the HD 98800 System

TL;DR

This study determines the metallicity of the quadruple-star system HD 98800 using high-resolution spectra, finding a sub-solar metallicity that aligns with pre-main sequence stellar models.

Contribution

First spectroscopic metallicity measurement of HD 98800, providing key data for testing stellar evolution models of PMS binaries.

Findings

Best-fit metallicity is [M/H] = -0.20±0.10.

Sub-solar metallicity yields better spectral fits.

Results are consistent with PMS evolutionary tracks.

Abstract

Pre-main sequence (PMS) binaries and multiples enable critical tests of stellar models if masses, metallicities, and luminosities of the component stars are known. We have analyzed high-resolution, high signal-to-noise echelle spectra of the quadruple-star system HD 98800 and using spectrum synthesis, computed fits to the composite spectrum for a full range of plausible stellar parameters for the components. We consistently find that sub-solar metallicity yields fits with lower $\chi^2$ values, with an overall best-fit of $[M/H] = -0.20\pm0.10$. This metallicity appears to be consistent with PMS evolutionary tracks for the measured masses and luminosities of the components of HD 98800 but additional constraints on the system and modelling are needed.