UCAC3 Proper Motion Survey. I. Discovery of New Proper Motion Stars in UCAC3 With 0".40/yr > mu > 0".18/yr Between Declinations -90 deg and -47 deg
NAVAL OBSERVATORY WASHINGTON DC
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This paper presents 442 new proper motion stellar systems in the southern sky between declinations -90 deg and -47 deg with 0.40yr mu 0.18yr. These systems constitute a 25.3 increase in new systems for the same region of the sky covered by previous SuperCOSMOS RECONS SCR searches that used Schmidt plates as the primary source of discovery. Among the new systems are 25 multiples, plus an additional 7 new common proper motion CPM companions to previously known primaries. All stars have been discovered using the third U.S. Naval Observatory USNO CCD Astrograph Catalog UCAC3. A comparison of the UCAC3 proper motions to those from the Hipparcos, Tycho-2, Southern Proper Motion SPM4, and SuperCOSMOS efforts is presented and shows that UCAC3 provides similar values and precision to the first three surveys. The comparison between UCAC3 and SuperCOSMOS indicates that proper motions in R.A. are systematically shifted in the SuperCOSMOS data but are consistent in decl. data, while overall showing a significantly higher scatter. Distance estimates are derived for stars having SuperCOSMOS Sky Survey BJ, R59F, and IIVN plate magnitudes and Two-Micron All Sky Survey infrared photometry. We find 15 systems estimated to be within 25 pc, including UPM 1710-5300 our closest new discovery estimated at 13.5 pc. Such new discoveries suggest that more nearby stars are yet to be found in these slower proper motion regimes, indicating that more work is needed to develop a complete map of the solar neighborhood.