Zeta Orionis A is a blue supergiant star that can be located in the constellation of Orion. The description is based on the spectral class. Zeta Orionis A is not part of the constellation but is within the borders of the constellation.
The Id of the star in the Yale Bright Star Catalogue is HR1948. The Id of the star in the Henry Draper catalogue is HD37742.
More details on star alternative names can be found at Star Names .
The location of the star in the night sky is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Zeta Orionis A, the location is 05 40 45.527 and -01 56 33.26 .
All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving 2.50 miliarcseconds/year towards the north and 4.00 miliarcseconds/year east if we saw them in the horizon.
The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 18.10 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.
Zeta Orionis A has a spectral type of O9.2IbvarNwk C. This means the star is a blue supergiant star.
|Primary / Proper / Traditional Name||Zeta Orionis A|
|Alternative Names||HD 37742, HR 1948|
|Spectral Type||O9.2IbvarNwk C|
|Constellation's Main Star||No|
|Multiple Star System||No / Unknown|
|Star Type||very luminous Supergiant Star|
|Right Ascension (R.A.)||05 40 45.527|
|Declination (Dec.)||-01 56 33.26|
|Proper Motion Dec.||2.50 milliarcseconds/year|
|Proper Motion RA.||4.00 milliarcseconds/year|
|Radial Velocity||18.10 km/s|
|Associated / Clustered Stars||Alnitak|
Zeta Orionis B