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AR Monocerotis - HD57364 - HIP35600

AR Monocerotis is a orange to red eclipsing luminous giant star that can be located in the constellation of Monoceros. The star can not be seen by the naked eye, you need a telescope to see it.

HIP35600 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD57364.

AR Monocerotis has alternative name(s), AR_Mon.

Location of AR Monocerotis

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 AR Monocerotis, the location is 07h 20m 48.45 and -05d15`35.7 .

Proper Motion of AR Monocerotis

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 -7.28 ± 0.65 miliarcseconds/year towards the north and 6.00 ± 1.02 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of AR Monocerotis

AR Monocerotis has a spectral type of K0II SB. This means the star is a orange to red luminous giant star. The star has a B-V Colour Index of 1.06 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,845 Kelvin.

AR Monocerotis Radius has been calculated as being 6.58 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 4,579,155.01.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 7.02. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

AR Monocerotis Apparent and Absolute Magnitudes

AR Monocerotis has an apparent magnitude of 8.73 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 1.52 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.38. 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 AR Monocerotis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.62 which gave the calculated distance to AR Monocerotis as 901.00 light years away from Earth or 276.24 parsecs. It would take a spaceship travelling at the speed of light, 901.00 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 3.39 which put AR Monocerotis at a distance of 962.13 light years or 294.99 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.

Variable Type of AR Monocerotis

The star is a eclipsing Beta Persei (Algol)/System with one or both giant or supergiant components variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. AR Monocerotis brightness ranges from a magnitude of 10.000 to a magnitude of 9.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

AR Monocerotis Facts

Alternative Names

Traditional/Proper NameAR Monocerotis
Short NameAR Mon
Hipparcos Library I.D.35600
Bonner DurchmusterungBDD-04 1915
Henry Draper Designation57364

Visual Facts

Star Typeluminous giant star
Absolute Magnitude1.52 / 1.38
Visual / Apparent Magnitude8.73
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)07h 20m 48.45
Declination (Dec.)-05d15`35.7
Galactic Latitude4.10 degrees
Galactic Longitude220.98 degrees
1997 Distance from Earth3.62 Parallax (milliarcseconds)
 901.00 Light Years
 276.24 Parsecs
2007 Revised Distance from Earth3.39 Parallax (milliarcseconds)
 962.13 Light Years
 294.99 Parsecs
Proper Motion Dec.-7.28 ± 0.65 milliarcseconds/year
Proper Motion RA.6.00 ± 1.02 milliarcseconds/year
B-V Index1.06
Radial Velocity11.92 ± 0.60 km/s
Spectral TypeK0II SB
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeBeta Persei (Algol)/System with one or both giant or supergiant components
Variable Magnitude Range (Brighter - Dimmer)9.000 - 10.000

Estimated Facts

Calculated Effective Temperature4,845 Kelvin

Sources and Links

SIMBAD SourceLink

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