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New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
| Photoelectric Photometry of Herbig Ae/be and Related Stars in the Vilnius Photometric System
A catalog of photoelectric photometry of 62 Herbig Ae/Be and relatedstars in the Vilnius system is presented. It contains stars down to V =12 mag located mainly in the northern hemisphere and observed in theperiod of 1994--1996.
| Stellar associations in the region of CMa
Forty-three early-type stars brighter than 9 mag at 1640 A were observedin the region of CMa with the Glazar Space Telescope. The observed starsare shown to compose three groups situated at distances of 320, 570, and1100 pc. The first two groups are B-associations, and the third is anO-association. It is concluded that the dust matter situated atdistances up to 1000 pc yields an interstellar extinction parameter of0.7 mag at 1640 A.
| An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
| Investigation of a Milky Way field in Canis Major
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79.1022C&db_key=AST
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Tekboynuz |
| Sað Açýklýk: | 06h57m21.48s |
| Yükselim: | -10°56'43.1" |
| Görünürdeki Parlaklýk: | 8.296 |
| Uzaklýk: | 10000000 parsek |
| özdevim Sað Açýklýk: | -1.8 |
| özdevim Yükselim: | 3.9 |
| B-T magnitude: | 8.195 |
| V-T magnitude: | 8.288 |
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