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The Vienna-KPNO search for Doppler-imaging candidate stars. I. A catalog of stellar-activity indicators for 1058 late-type Hipparcos stars
We present the results from a spectroscopic Ca ii H&K survey of 1058late-type stars selected from a color-limited subsample of the Hipparcoscatalog. Out of these 1058 stars, 371 stars were found to showsignificant H&K emission, most of them previously unknown; 23% withstrong emission, 36% with moderate emission, and 41% with weak emission.These spectra are used to determine absolute H&K emission-linefluxes, radial velocities, and equivalent widths of theluminosity-sensitive Sr ii line at 4077 Ä. Red-wavelengthspectroscopic and Strömgren y photometric follow-up observations ofthe 371 stars with H&K emission are used to additionally determinethe absolute Hα -core flux, the lithium abundance from the Li i6708 Å equivalent width, the rotational velocity vsin i, theradial velocity, and the light variations and its periodicity. Thelatter is interpreted as the stellar rotation period due to aninhomogeneous surface brightness distribution. 156 stars were found withphotometric periods between 0.29 and 64 days, 11 additional systemsshowed quasi-periodic variations possibly in excess of ~50 days. Further54 stars had variations but no unique period was found, and four starswere essentially constant. Altogether, 170 new variable stars werediscovered. Additionally, we found 17 new SB1 (plus 16 new candidates)and 19 new SB2 systems, as well as one definite and two possible new SB3systems. Finally, we present a list of 21 stars that we think are mostsuitable candidates for a detailed study with the Doppler-imagingtechnique. Tables A1--A3 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| Narrow- and intermediate-band H-alpha and O I 7774 A photometry and RETICON spectroscopy of SX Cassiopeiae
Observations of the 36.57-day eclipsing binary SX Cas made on eightnights during February and March 1979 with pairs of intermediate- andnarrow-band filters centered on the wavelengths of the Balmer H-alphaline and the O I 7774 A triplet are discussed. In addition, a reticonspectrum covering a wavelength range of 4750 A to 7700 A was obtained inSeptember 1979, showing strong H-beta and H-alpha emission lines as wellas absorption features of the K-giant component of the system. From thephotometry, strong H-alpha emission is found at all the orbital phasessampled. However, no appreciable O I 7774 A line emission is detected.It is noted that the strong H-alpha emission is consistent with thepresence of significant amounts of circumstellar and circumbinary gas.From the observations, it appears that the H-alpha emitting region iscentered chiefly on the primary component, but the gas is partiallyeclipsed by the larger cool giant during primary eclipse. TheH-alpha-emitting region therefore appears larger than the dimensions ofthe stellar components. In addition, the apparent nonrepeatability ofthe H-alpha emission strength from one orbital cycle to the next impliesthat relatively rapid changes in the extent or quantity of gas occur inthe system.
| The complicated giant binary SX Cas.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..500K&db_key=AST
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| Takýmyýldýz: | Zincirli Prenses |
| Sað Açýklýk: | 00h10m46.34s |
| Yükselim: | +55°20'34.1" |
| Görünürdeki Parlaklýk: | 8.069 |
| Uzaklýk: | 205.761 parsek |
| özdevim Sað Açýklýk: | -10.3 |
| özdevim Yükselim: | -5.9 |
| B-T magnitude: | 9.162 |
| V-T magnitude: | 8.16 |
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