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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.
| Spectral types for early-type stars observed by SKYLAB
MK spectral types are presented for 246 early-type stars observed withthe S-019 ultraviolet stellar astronomy experiment on Skylab. K-linetypes are also given where applicable, and various peculiar stars areidentified. The peculiar stars include five silicon stars, a shell star,a helium-rich star, a silicon-strontium star, a chromium-europium star,and two marginal metallic-line stars.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Irmak |
| Sað Açýklýk: | 03h08m54.19s |
| Yükselim: | -18°58'09.2" |
| Görünürdeki Parlaklýk: | 7.186 |
| Uzaklýk: | 277.778 parsek |
| özdevim Sað Açýklýk: | 14.2 |
| özdevim Yükselim: | 5.4 |
| B-T magnitude: | 7.249 |
| V-T magnitude: | 7.192 |
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