1999/07/12 by Dainis Dravins, Dravins, Dainis, L. Lindegren +5
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9907145
13 pages, 2 figures. Accepted for publication in Astronomy & Astrophysics (main journal)
openalex publication_date 1999/07/12 · arxiv created 1999/07/14 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
High-accuracy astrometry permits the determination of not only stellar\ntangential motion, but also the component along the line-of-sight. Such\nnon-spectroscopic (i.e. astrometric) radial velocities are independent of\nstellar atmospheric dynamics, spectral complexity and variability, as well as\nof gravitational redshift. Three methods are analysed: (1) changing annual\nparallax, (2) changing proper motion and (3) changing angular extent of a\nmoving group of stars. All three have significant potential in planned\nastrometric projects. Current accuracies are still inadequate for the first\nmethod, while the second is marginally feasible and is here applied to 16\nstars. The third method reaches high accuracy (<1 km/s) already with present\ndata, although for some clusters an accuracy limit is set by uncertainties in\nthe cluster expansion rate.\n