Cool Subdwarf Investigations III: Dynamical Masses of Low Metallicity Subdwarfs

Abstract

We report dynamical mass measurements for the components of the previously known double-lined spectroscopic subdwarfs G 006-026 B and C using the Fine Guidance Sensors (FGS) on the Hubble Space Telescope. To build the empirical mass-luminosity relation for low metallicity subdwarfs, we collect four other subdwarf systems with dynamical masses that we compare to theoretical models for various metallicities on the mass-luminosity relation. For most stars, they fall in the regions where the models predict to be low metallicity. This effort highlights the scarcity of dynamical masses for subdwarfs and that much work remains to be done to improve the mass errors and metallicity measurements of low mass subdwarfs in our Galaxy.

arXiv commentaccepted for publication in Astronomical Journal

References in corpus (23)

• Validation of the new Hipparcos reduction
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Accurate masses and radii of normal stars: modern results and applications
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• M-Subdwarfs: Spectroscopic Classification and the Metallicity Scale
• Post-T Tauri Stars in the Nearest OB Association
• Revised metallicity classes for low-mass stars: dwarfs (dM), subdwarfs (sdM), extreme subdwarfs (esdM), and ultra subdwarfs (usdM)
• 99 Herculis: Host to a Circumbinary Polar-ring Debris Disk
• The Solar Neighborhood XIII: Parallax Results from the CTIOPI 0.9-m Program -- Stars with mu >= 1"/year (MOTION Sample)
• Metallicity of solar-type stars with debris discs and planets
• Cool Subdwarf Investigations (CSI) I: New Thoughts for the Spectral Types of K and M Subdwarfs
• On a new Near-Infrared method to estimate the absolute ages of star clusters: NGC3201 as a first test case
• Constraining Globular Cluster Age Uncertainties Using the IR Color-Magnitude Diagram
• The NLTE Barium Abundance in Dwarf Stars in the Metallicity Range of -1 < [Fe/H] < +0.3
• Cool Subdwarf Investigations II: Multiplicity
• A New Sample of Cool Subdwarfs from SDSS: Properties and Kinematics
• Observations of Binary Stars with the Differential Speckle Survey Instrument. V. Toward an Empirical Metal-Poor Mass-Luminosity Relation
• New metallicity calibration down to [Fe/H] = -2.75 dex
• Lucky Imaging of M subdwarfs
• Ages of White Dwarf-Red Subdwarf Systems
• The cluster ages experiment (CASE). VII. Analysis of two eclipsing binaries in the globular cluster NGC 6362
• Carbon Abundances of Metal-Poor Star Determined from the C I 1.068-1.069 micron Lines

Cited by in corpus (9)

• A 62-minute orbital period black widow binary in a wide hierarchical triple
• M subdwarf research. I. Identification, modified classification system, and sample construction
• Stars in the Local Galactic Thick Disk and Halo in Gaia EDR3: A catalogue of Half a Million Local Main-sequence Stars with Photometric Metallicities
• The Solar Neighborhood XLII. Parallax Results from the CTIOPI 0.9-m Program --- Identifying New Nearby Subdwarfs Using Tangential Velocities and Locations on the H-R Diagram
• Combining Hipparcos and Gaia data for the study of binaries: the BINARYS tool
• Microlens mass determination for Gaia's predicted photometric events
• Orbital parallax of binary systems compared to GAIA DR3 and the parallax zero-point offset at bright magnitudes
• Hubble Space Telescope Astrometry of the Metal-Poor Visual Binary $\mu$ Cassiopeiae: Dynamical Masses, Helium Content, and Age
• Metal-Depleted Brown Dwarfs