The nearby spiral density-wave structure of the Galaxy: Line-of-sight velocities of the Gaia DR2 main-sequence A, F, G, and K stars

Evgeny Griv, Michael Gedalin, I. Chun Shih, Li Gang Hou, Ing Guey Jiang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Distances and velocities of main-sequence A, F, G, and K stars are collected from the second data release of ESA's Gaia astrometric mission. This material is analysed to find evidence of radial and azimuthal systematic non-circular motions of stars in the solar neighbourhood on the assumption that the system is subject to spiral density waves (those produced by a spontaneous disturbance, a central bar, or an external companion), developing in the Galactic disc. Data analysis of line-of-sight velocities of stars selected within 2 kpc from the Sun and 500 pc from the Galactic mid-plane with distance accuracies of <10 per cent makes evident that a radial wavelength of the wave pattern is 1.1-1.6 kpc and a phase of the wave at the Sun's location in the Galaxy is 55°-95°. Respectively, the Sun is situated at the inner edge of the nearest Orion spiral arm segment. Thus, the local Orion arm is a part of a predominant density-wave structure of the system. The spiral structure of the Galaxy has an oscillating nature corresponding to a concept of the Lin-Shu-type moderately growing in amplitude, tightly wound, and rigidly rotating density waves.

Original languageEnglish
Pages (from-to)2111-2126
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume493
Issue number2
DOIs
StatePublished - 1 Apr 2020

Keywords

  • Galaxy: kinematics and dynamics
  • Galaxy: structure
  • galaxies: spiral

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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