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Theta1 Orionis A - HD37020 - HIP26220

Theta1 Orionis A is a blue star that can be located in the constellation of Orion. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Theta1 Orionis A is the Bayer Classification for the star. HIP26220 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD37020.

Theta1 Orionis A has alternative name(s), 41 Orionis , 41 Ori. Theta1 Orionis A is a multiple star system with 4 stars orbiting in its solar system.

Location of Theta1 Orionis A

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 Theta1 Orionis A, the location is 05h 35m 15.82 and -05 d 23 ` 14.3 .

Physical Properties (Colour, Radius) of Theta1 Orionis A

Theta1 Orionis A has a spectral type of O7. This means the star is a blue star. The star is 7920.00000000 Parsecs from the Galactic Centre or terms of Light Years is 25832.1368448000000000s. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Theta1 Orionis A Apparent and Absolute Magnitudes

Theta1 Orionis A has an apparent magnitude of 4.98 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 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 Theta1 Orionis A

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -2.00 which gave the calculated distance to Theta1 Orionis A as -1630.82 light years away from Earth or -500 parsecs. It would take a spaceship travelling at the speed of light, -1630.82 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

The star's Galacto-Centric Distance is 7,920.00 Parsecs or 25,832.14 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.

Theta1 Orionis A Facts

Alternative Names

Short Name41 Ori
Bayer DesignationTheta1 Orionis A
Alternative Name(s)41 Orionis
Hipparcos Library I.D.26220
Henry Draper Designation37020

Visual Facts

Star Type star
Visual / Apparent Magnitude4.98
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)05h 35m 15.82
Declination (Dec.)-05 d 23 ` 14.3
Galactic Latitude-19.39 degrees
Galactic Longitude209.01 degrees
1997 Distance from Earth-2.00 Parallax (milliarcseconds)
 -1630.82 Light Years
 -500 Parsecs
Galacto-Centric Distance25,832.14 Light Years / 7,920.00 Parsecs
B-V Index-99.00
Radial Velocity28.30 ± 1.00 km/s
Spectral TypeO7
Colour(O) blue
Stars in Solar System4

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
37020B6.700001957
37021BD8.000001957
BH11.100001934

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