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Chi1 Orionis, 54 Orionis, HD39587, HIP27913, HR2047

Chi1 Orionis is a white to yellow main sequence dwarf star that can be located in the constellation of Orion. Chi1 Orionis is the brightest star in Orion based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Chi1 Orionis is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR2047. HIP27913 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD39587. The Gliese ID of the star is Gliese GL222 AB. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Ref : Star Names.

Location of Chi1 Orionis

The location of the star in the galaxy 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 Chi1 Orionis, the location is 05h 54m 23.08 and +20d 16` 35.1 .

Proper Motion of Chi1 Orionis

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 -99.51 ± 0.16 miliarcseconds/year towards the north and -162.54 ± 0.27 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 us is -13.17000 km/s with an error of about 0.21 km/s .

Chi1 Orionis Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 1.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Chi1 Orionis

Chi1 Orionis has a spectral type of G0V. This means the star is a white to yellow main sequence dwarf star. The star is 7409.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24165.4421569600000000s. The star has a B-V Colour Index of 0.59 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,931 Kelvin.

Chi1 Orionis Radius has been calculated as being 1.02 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 706,457.17.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.02. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -0.04 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Chi1 Orionis Apparent and Absolute Magnitudes

Chi1 Orionis has an apparent magnitude of 4.39 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 4.70 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.70. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Chi1 Orionis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 115.43 which gave the calculated distance to Chi1 Orionis as 28.26 light years away from Earth or 8.66 parsecs. It would take a spaceship travelling at the speed of light, 28.26 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 115.43 which put Chi1 Orionis at a distance of 28.26 light years or 8.66 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

The star's Galacto-Centric Distance is 7,409.00 Parsecs or 24,165.44 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Chi1 Orionis Facts

Alternative Names

Flamsteed Name54 Orionis
Flamsteed Short Name54 Ori
Bayer DesignationChi1 Orionis
Hipparcos Library I.D.27913
Yale Bright Star Catalogue (HR) Id2047
Bonner DurchmusterungBD+20 1162
Gliese ID222 AB
Henry Draper Designation39587

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude4.70 / 4.70
Visual / Apparent Magnitude4.39
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)05h 54m 23.08
Declination (Dec.)+20d 16` 35.1
Galactic Latitude-2.73 degrees
Galactic Longitude188.46 degrees
1997 Distance from Earth115.43 Parallax (milliarcseconds)
 28.26 Light Years
 8.66 Parsecs
2007 Revised Distance from Earth115.43 Parallax (milliarcseconds)
 28.26 Light Years
 8.66 Parsecs
Galacto-Centric Distance24,165.44 Light Years / 7,409.00 Parsecs
Proper Motion Dec.-99.51 ± 0.16 milliarcseconds/year
Proper Motion RA.-162.54 ± 0.27 milliarcseconds/year
B-V Index0.59
Radial Velocity-13.17 ± 0.21 km/s
Iron Abundance-0.04 ± 9.99 Fe/H
Spectral TypeG0V
Associated / Clustered StarsChi2 Orionis
Colour(G) White to Yellow

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature5,931 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Chi1 Orionis in Orion

Chi1 Orionis (Chi1 Orionis) Location in Orion

The map was generated using Night Vision, an awesome free application by Brian Simpson.

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