2000/05/24 by R. P. Olling, R. Olling, Olling, R. P. +2 · 4 citations
Physics and Astronomy · #Astrometry #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics (astro-ph) #Circular motion #Classical mechanics #FOS: Physical sciences #Galaxy #Galaxy formation and evolution #Geometry #History and Developments in Astronomy #Interacting galaxy #Irregular galaxy #Parallax #Physics #Rotation (mathematics) #Satellite galaxy #Spiral galaxy #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0005484
published in arXiv (Cornell University) (Cornell University) · 35 pages, 15 figures
arxiv created 2000/05/24 · openalex publication_date 2000/05/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Accurate distances to stars and galaxies allow for significant tests of stellar evolution, galaxy formation and evolution and cosmology. NASA's Space Interferometry Mission (SIM) will obtain precision [1-30 microarcsec] astrometry for 10-20k objects brighter than V=20 mag. In this paper we discuss a method to determine the distance of nearby spiral galaxies using the technique of rotational parallaxes, and show that it is possible to achieve distance errors of only a few percent. With such distances at hand, it becomes possible to determine an accurate zero-point for the Tully-Fisher relation, one of the tools to measure distances throughout the universe. The rotational parallax method employs the common orbital motions of a of stars within a galaxy to determine their distance. For stars on circular orbits, the two proper motions and the radial velocity suffice to determine the inclination of the orbit, the rotational velocity and the distance. Several factors complicate the application of this simple technique to real galaxies: 1) the target galaxy may have substantial space-motion, 2) stars in real galaxies are not on circular orbits (e.g. due to spiral-arm streaming motions or induced by random motions), 3) stars in the galaxy are at significantly different distances from the Sun (the near side of M 31 is ~5% closer than the far side). Notwithstanding these complication, distances can be determined to within several percent for the nearest spirals. (abridged)