The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. I/237 Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ.122.3466M and Mason et al. Naval Observatory, Washington Worley and Douglass 1997A&AS.125.523W, Cat. Prior to this, three major updates have been published (Worley and Douglass 1984, " Washington Visual Double Star Catalog, 1984.0", U.S. The WDS is continually updated as published data become available. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS Jeffers and van den Bos, Publ. This result demonstrates the importance of vetting of targets with measured astrometric acceleration for short-period stellar companions prior to conducting targeted direct imaging surveys for wide-orbit substellar companions.VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2014) We present the first constraints on the orbit of the inner companion, and demonstrate that it is a plausible cause of the astrometric acceleration. In this paper we explore the origin of the astrometric acceleration by modeling the signal induced by a wide-orbit M8 companion discovered with the Gemini Planet Imager, as well as the effects of an inner short-period spectroscopic companion discovered a century ago but not since followed up. The small but significant amplitude of the acceleration made more » HR 1645 a promising candidate for targeted searches for brown dwarf and planetary-mass companions around nearby, young stars. This signal is consistent with either a stellar companion with a moderate mass ratio (q ~ 0.5) on a short period (P < 1 yr), or a substellar companion at a separation wide enough to be resolved with ground-based high-contrast imaging instruments long-period equal-mass ratio stellar companions that are also consistent with the measured acceleration are excluded with previous imaging observations. The ~500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. =, respectively, and their spectral line broadening indicates that they represent extremes of fast and slow projected rotational velocity, respectively.
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