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RW Geminorum, HD250371, HIP28537

RW Geminorum is a blue eclipsing star that can be located in the constellation of Gemini. The star can not be seen by the naked eye, you need a telescope to see it.

HIP28537 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD250371.

RW Geminorum has alternative name(s), RW Gem.

Location of RW Geminorum

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 RW Geminorum, the location is 06h 01m 28.06 and +23d 08` 27.5 .

Proper Motion of RW Geminorum

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 -3.10 ± 1.37 miliarcseconds/year towards the north and 4.76 ± 2.95 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 0.30000 km/s with an error of about 7.40 km/s .

RW Geminorum 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 240.0000000 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 RW Geminorum

RW Geminorum has a spectral type of B6V comp SB. This means the star is a blue star. The star has a B-V Colour Index of 0.1 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 8,455 Kelvin.

RW Geminorum Radius has been calculated as being 0.48 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 333,513.62.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 0.68. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

RW Geminorum Apparent and Absolute Magnitudes

RW Geminorum has an apparent magnitude of 9.68 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 4.79 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.04. 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 RW Geminorum

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 10.53 which gave the calculated distance to RW Geminorum as 309.75 light years away from Earth or 94.97 parsecs. It would take a spaceship travelling at the speed of light, 309.75 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 7.45 which put RW Geminorum at a distance of 437.80 light years or 134.23 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.

Variable Type of RW Geminorum

The star is a eclipsing Beta Persei (Algol)/Semi-Detached System (subtype) 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. This is a some uncertainty as to the type but the type mentioned is the current variable star classification for this star. RW Geminorum brightness ranges from a magnitude of 11.840 to a magnitude of 9.610 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.

RW Geminorum Facts

Alternative Names

Traditional/Proper NameRW Geminorum
Short NameRW Gem
Hipparcos Library I.D.28537
Bonner DurchmusterungBD+23 1151
Henry Draper Designation250371

Visual Facts

Star Type star
Absolute Magnitude4.79 / 4.04
Visual / Apparent Magnitude9.68
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)06h 01m 28.06
Declination (Dec.)+23d 08` 27.5
Galactic Latitude0.12 degrees
Galactic Longitude186.80 degrees
1997 Distance from Earth10.53 Parallax (milliarcseconds)
 309.75 Light Years
 94.97 Parsecs
2007 Revised Distance from Earth7.45 Parallax (milliarcseconds)
 437.80 Light Years
 134.23 Parsecs
Proper Motion Dec.-3.10 ± 1.37 milliarcseconds/year
Proper Motion RA.4.76 ± 2.95 milliarcseconds/year
B-V Index0.10
Radial Velocity0.30 ± 7.40 km/s
Spectral TypeB6V comp SB
Colour(B) blue

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeBeta Persei (Algol)/Semi-Detached System (subtype) probably
Variable Magnitude Range (Brighter - Dimmer)9.610 - 11.840

Estimated Facts

Luminosity (x the Sun)240.0000000
Calculated Effective Temperature8,455 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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