Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

HD 193138


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

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.

The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.

Spectroscopic tests of photoelectric stellar classification of abnormal stars
Spectroscopic classification is obtained for 169 northern A5-G0 starspredicted by Olsen (1979, 1980) to have abnormal spectra on the basis ofStromgren four-color photometry. The success in identifying reddenedearly type stars was nearly 100 percent, for Am and early type weaklined stars about 75 percent, for stars above main sequence about 50percent, for composite spectra about 25 percent, and for Ap and LambdaBoo stars 0 percent. Thus photoelectric photometry is a successful firststep in discovering stars of the more extreme spectroscopicabnormalities.

Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:りゅう座
Right ascension:20h13m18.48s
Declination:+71°06'30.3"
Apparent magnitude:7.816
Distance:201.613 parsecs
Proper motion RA:14.8
Proper motion Dec:29
B-T magnitude:8.247
V-T magnitude:7.852

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 193138
TYCHO-2 2000TYC 4450-1661-1
USNO-A2.0USNO-A2 1575-04376871
HIPHIP 99640

→ Request more catalogs and designations from VizieR