A Very Metal-poor RR Lyrae Star with a Disk Orbit Found in the Solar Neighborhood

نویسندگان

چکیده

Abstract Metal-deficient stars are important tracers for understanding the early formation of Galaxy. Recent large-scale surveys with both photometric and spectroscopic data have reported an increasing number metal-deficient whose kinematic features consistent those disk stellar populations. We report discovery RR Lyrae variable (hereafter RRL) that is located within thick has orbit thick-disk kinematics. Our target RRL (HD 331986) at around 1 kpc from Sun and, V ≃ 11.3, among ∼130 brightest RRLs known so far. However, this object scarcely been studied because it in midplane Galaxy, a Galactic latitude –1°. Its near-infrared spectrum (0.91–1.32 μ m) shows no absorption line except hydrogen lines Paschen series, suggesting [Fe/H] ≲ –2.5. It most RRL, least orbits kinematics, although we cannot determine to which halo belongs. This unique would provide us essential clues studying inner Galaxy further investigations, including high-resolution optical spectroscopy.

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ژورنال

عنوان ژورنال: The Astrophysical Journal

سال: 2022

ISSN: ['2041-8213', '2041-8205']

DOI: https://doi.org/10.3847/1538-4357/ac3483