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Phi2 Orionis, 40 Orionis, HD37160, HIP26366, HR1907

Phi2 Orionis is a white to yellow subgiant star 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.

Phi2 Orionis's Alternative Names

Phi2 Orionis (Phi02 Ori) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR1907. HIP26366 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD37160.

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 40 Orionis with it shortened to 40 Ori.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+09 898.

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

Location of Phi2 Orionis

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 Phi2 Orionis, the location is 05h 36m 54.33 and +09° 17` 29.1 .

Proper Motion of Phi2 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 -305.57 ± 0.15 miliarcseconds/year towards the north and 97.24 ± 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 98.96000 km/s with an error of about 0.09 km/s .

Phi2 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 34.82 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of Phi2 Orionis

Phi2 Orionis has a spectral type of G8III-IV. This means the star is a white to yellow subgiant star. The star is 7,434.00 Parsecs from the Galactic Centre or terms of Light Years is 24,246.98 s. The star has a B-V Colour Index of 0.95 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,948 Kelvin.

Phi2 Orionis Radius has been calculated as being 6.89 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 4,791,984.35.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 6.95. 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 -0.54 with an error value of 0.03 Fe/H with the Sun has a value of 1 to put it into context.

Phi2 Orionis Apparent and Absolute Magnitudes

Phi2 Orionis has an apparent magnitude of 4.09 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 1.33 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.31. 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 Phi2 Orionis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 28.10 which gave the calculated distance to Phi2 Orionis as 116.07 light years away from Earth or 35.59 parsecs. It would take a spaceship travelling at the speed of light, 116.07 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 27.76 which put Phi2 Orionis at a distance of 117.49 light years or 36.02 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 7,434.00 Parsecs or 24,246.98 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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Phi2 Orionis Facts

Visual Facts

Primary / Proper / Traditional NamePhi2 Orionis
Alternative NamesPhi02 Ori, HD 37160, HIP 26366, HR 1907, 40 Orionis, 40 Ori, BD+09 898
Spectral TypeG8III-IV
Multiple Star SystemYes
Star TypeSubgiant Star
Colour white to yellow
GalaxyMilky Way
Absolute Magnitude1.33 / 1.31
Visual / Apparent Magnitude4.09
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)05h 36m 54.33
Declination (Dec.)+09° 17` 29.1
Galactic Latitude-11.95 degrees
Galactic Longitude195.84 degrees
1997 Distance from Earth28.10 Parallax (milliarcseconds)
 116.07 Light Years
 35.59 Parsecs
2007 Distance from Earth27.76 Parallax (milliarcseconds)
 117.49 Light Years
 36.02 Parsecs
Galacto-Centric Distance24,246.98 Light Years / 7,434.00 Parsecs
Proper Motion Dec.-305.57 ± 0.15 milliarcseconds/year
Proper Motion RA.97.24 ± 0.27 milliarcseconds/year
B-V Index0.95
Radial Velocity98.96 ± 0.09 km/s
Iron Abundance-0.54 ± 0.03 Fe/H
Semi-Major Axis4489.00
Stellar Luminosity (Lsun)34.82
Associated / Clustered StarsPhi1 Orionis

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Facts

Calculated Effective Temperature4,948 Kelvin

Sources and Links

SIMBAD SourceLink

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