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Theta1 Orionis A, 41 Orionis A, HD37020, HIP26220, HR1893

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

Theta1 Orionis A's Alternative Names

Theta1 Orionis A (The01 Ori) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR1893. 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.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 41 Orionis A with it shortened to 41 Ori A.

More details on star alternative names can be found at Star Names .

Location of Theta1 Orionis A

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

Physical Properties (Colour) of Theta1 Orionis A

Theta1 Orionis A has a spectral type of O7. This means the star is a blue multiple star system. The star is 7,920.00 Parsecs from the Galactic Centre or terms of Light Years is 25,832.14 s.

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. Using the supplied 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.

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Theta1 Orionis A Facts

Visual Facts

Primary / Proper / Traditional NameTheta1 Orionis A
Alternative NamesThe01 Ori, HD 37020, HIP 26220, HR 1893, 41 Orionis A, 41 Ori A
Spectral TypeO7
Multiple Star SystemYes
Star TypeMultiple Star System
Colour blue
GalaxyMilky Way
Visual / Apparent Magnitude4.98
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)05h 35m 15.82
Declination (Dec.)-05 ° 23` 14.3
Galactic Latitude-19.39 degrees
Galactic Longitude209.01 degrees
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
Semi-Major Axis8825.00
Associated / Clustered StarsTheta1 Orionis C
Theta1 Orionis D
Theta2 Orionis

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Sources and Links

SIMBAD SourceLink

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

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