Home     Per cominciare     Sopravvivere Nell'Universo    
Inhabited Sky
    News@Sky     Astro Foto     La collezione     Forum     Blog New!     FAQ     Stampa     Login  

HD 39104


Contenuti

Immagini

Carica la tua immagine

DSS Images   Other Images


Articoli relazionati

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.

Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.

The spectral classification of chromospherically active binary stars with composite spectra
This paper presents and analyzes blue and red-wavelength high-resolutionspectra of twelve chromospherically active binary or triple systems withcomposite spectra. Spectral classifications for the individual stellarcomponents are derived by means of the 'spectrum-synthesis' techniqueand are compared to stellar evolutionary models and observed massesand/or mass ratios. Also presented is a carefully selected set of MKreference stars of luminosity class III, IV, and V, and spectral typeA9-K5, and v sin i less than 10 km/s, to cover the spectral range of thecomponents of chromospherically active binary systems of the RSCVn-type. New values of v sin i are determined for some of the referenceand program stars. Two spectroscopic binaries have been discovered.

Sottometti un nuovo articolo


Link relazionati

  • - Nessun link trovato -
Sottometti un nuovo link


Membro dei seguenti gruppi:


Osservazione e dati astrometrici

Costellazione:Orione
Ascensione retta:05h50m03.28s
Declinazione:-05°53'53.4"
Magnitudine apparente:8.202
Distanza:176.991 parsec
Moto proprio RA:-4.2
Moto proprio Dec:-32.6
B-T magnitude:9.452
V-T magnitude:8.306

Cataloghi e designazioni:
Nomi esatti   (Edit)
HD 1989HD 39104
TYCHO-2 2000TYC 4780-1245-1
USNO-A2.0USNO-A2 0825-01700611
HIPHIP 27552

→ Richiesta di ulteriori cataloghi da VizieR