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Encounters of the Sun with Nearby Stars in the Past and Future
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| The near-IR NA I doublet and CA II triplet in late-type stars and the determination of stellar atmosphere parameters
CCD spectroscopic observations in the near-IR (7990-8680 A) for a sampleof 144 late type stars are presented. The dependence of the Na I doublet(8183 and 8194 A) and the Ca II triplet (8498, 8542 and 8662 A) onstellar atmospheric parameters is investigated. It is confirmed in starsof spectral types later than G0 a dependence of line strength oneffective temperature, surface gravity, and metallicity in goodagreement with previous studies. However, the present sample containsmany more very late type stars than previous studies, and these starsshow a strong dependence of Ca-II triplet strength on temperature. Theselines, together with the (R - I) color index which is known to be a goodtemperature indicator, were used to estimate the metal abundance and thesurface gravity of the present program stars.
| Photographic astrometry of binary and proper-motion stars
Plate series obtained at the 61-cm Sproul refractor of SwarthmoreCollege were processed during the time October 1982 to December 1983.Parts of some plate series had been measured previously. The presentinvestigation involves an evaluation of the entire material, taking intoaccount 58 trigonometric parallaxes and 14 binary-star mass ratios.Table I lists the parallax results. The measured components of theannual motion are to three decimals of arc seconds. A summary of themass-ratio results is provided in a second table. All observed objectsare briefly discussed.
| Some Cross-Reference Lists for the Catalog of Possible Nearby Stars
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| The space distribution of late type stars in a North galactic pole region.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1962AJ.....67...37U&db_key=AST
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Av Kopekleri |
| Sað Açýklýk: | 12h16m43.30s |
| Yükselim: | +44°24'07.2" |
| Görünürdeki Parlaklýk: | 9.135 |
| Uzaklýk: | 22.727 parsek |
| özdevim Sað Açýklýk: | 5.7 |
| özdevim Yükselim: | -23.1 |
| B-T magnitude: | 11.144 |
| V-T magnitude: | 9.301 |
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