The Most Metal-Poor Quadruple System of Subdwarfs G89-14

Abstract

The system of subdwarfs G89-14 is one of the most metal-poor multiple stars with an atmospheric metal abundance $[m/H]=-1.9$. Speckle interferometry at the 6-m BTA telescope has revealed that G89-14 consists of four components. Measurements of the magnitude difference between the components and published data have allowed their masses to be estimated: $M_A\approx 0.67M_{\odot }$, $M_B\approx 0.24M_{\odot }$, $M_C\approx 0.33M_{\odot }$, and $M_D\approx 0.22M_{\odot }$. The ratio of the orbital periods of the subsystems has been obtained, 0.52 yr : 3 000 yr : 650 000 yr (1:5769:1250000), indicative of a high degree of hierarchy of G89-14 and its internal dynamical stability. The calculated Galactic orbital elements and the low metallicity of the quadruple system suggest that it belongs to the Galactic halo.

5 pages, 3 figures

References in corpus (1)

• The EMCCD-Based Speckle Interferometer of the BTA 6-m Telescope: Description and First Results

Cited by in corpus (2)

• Multiplicity and period distribution of Population II field stars in solar vicinity
• The first galactic stars and chemical enrichment in the halo