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OP Andromedae, HD9746, HIP7493

OP Andromedae is a orange to red eclipsing binary system star that can be located in the constellation of Andromeda. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP7493 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD9746.

OP Andromedae has alternative name(s), OP And.

Location of OP Andromedae

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 OP Andromedae, the location is 01h 36m 27.21 and +48d 43` 22.2 .

Proper Motion of OP Andromedae

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 -17.81 ± 0.32 miliarcseconds/year towards the north and -16.08 ± 0.41 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 -42.67000 km/s with an error of about 0.14 km/s .

OP Andromedae 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 82.0000000 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 OP Andromedae

OP Andromedae has a spectral type of K1III:. This means the star is a orange to red star. The star is 7500.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24462.2508000000000000s. The star has a B-V Colour Index of 1.23 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,439 Kelvin.

OP Andromedae Radius has been calculated as being 11.70 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 8,143,501.09.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 14.27. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

OP Andromedae Apparent and Absolute Magnitudes

OP Andromedae has an apparent magnitude of 6.20 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 0.65 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.22. 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 OP Andromedae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.77 which gave the calculated distance to OP Andromedae as 419.77 light years away from Earth or 128.70 parsecs. It would take a spaceship travelling at the speed of light, 419.77 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 6.36 which put OP Andromedae at a distance of 512.84 light years or 157.23 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 7,500.00 Parsecs or 24,462.25 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of OP Andromedae

The star is a eclipsing binary system RS Canum Venaticorum 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. OP Andromedae brightness ranges from a magnitude of 6.413 to a magnitude of 6.253 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 2.4 days (variability).

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.

OP Andromedae Facts

Alternative Names

Traditional/Proper NameOP Andromedae
Short NameOP And
Hipparcos Library I.D.7493
Bonner DurchmusterungBD+47 460
Henry Draper Designation9746

Visual Facts

Star Type star
Absolute Magnitude0.65 / 0.22
Visual / Apparent Magnitude6.20
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)01h 36m 27.21
Declination (Dec.)+48d 43` 22.2
Galactic Latitude-13.48 degrees
Galactic Longitude130.54 degrees
1997 Distance from Earth7.77 Parallax (milliarcseconds)
 419.77 Light Years
 128.70 Parsecs
2007 Revised Distance from Earth6.36 Parallax (milliarcseconds)
 512.84 Light Years
 157.23 Parsecs
Galacto-Centric Distance24,462.25 Light Years / 7,500.00 Parsecs
Proper Motion Dec.-17.81 ± 0.32 milliarcseconds/year
Proper Motion RA.-16.08 ± 0.41 milliarcseconds/year
B-V Index1.23
Radial Velocity-42.67 ± 0.14 km/s
Spectral TypeK1III:
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeRS Canum Venaticorum
Mean Variability Period in Days2.360
Variable Magnitude Range (Brighter - Dimmer)6.253 - 6.413

Estimated Facts

Luminosity (x the Sun)82.0000000
Calculated Effective Temperature4,439 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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