9 Geminorum is a blue pulsating very luminous supergiant star that can be located in the constellation of Gemini. 9 Geminorum is the brightest star in Gemini based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
HIP29840 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD43384.
9 Geminorum has alternative name(s), PX Gem.
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 9 Geminorum, the location is 06h 16m 58.71 and +23d44`27.3 .
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 180000.0000000 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.
9 Geminorum has a spectral type of B3Ia. This means the star is a blue supergiant star. The star has a B-V Colour Index of 0.44 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,276 Kelvin.
9 Geminorum Radius has been calculated as being 28.55 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 19,863,206.21.km. 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 -0.14 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.
9 Geminorum has an apparent magnitude of 6.24 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 -2.79 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.
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.56 which gave the calculated distance to 9 Geminorum as 2090.79 light years away from Earth or 641.03 parsecs. It would take a spaceship travelling at the speed of light, 2090.79 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.
The star is a pulsating Alpha Cygnus 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. 9 Geminorum brightness ranges from a magnitude of 6.388 to a magnitude of 6.333 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 13.7 days (variability).
|Traditional/Proper Name||9 Geminorum|
|Flamsteed Name||9 Geminorum|
|Flamsteed Short Name||9 Gem|
|Short Name||PX Gem|
|Hipparcos Library I.D.||29840|
|Bonner Durchmusterung||BD+23 1275|
|Henry Draper Designation||43384|
|Star Type||supergiant star|
|Visual / Apparent Magnitude||6.24|
|Naked Eye Visible||Yes - Magnitudes|
|Right Ascension (R.A.)||06h 16m 58.71|
|Galactic Latitude||3.53 degrees|
|Galactic Longitude||187.99 degrees|
|1997 Distance from Earth||1.56 Parallax (milliarcseconds)|
|2090.79 Light Years|
|Radial Velocity||13.20 ± 2.90 km/s|
|Iron Abundance||-0.14 ± 9.99 Fe/H|
|Variable Star Class||Pulsating|
|Variable Star Type||Alpha Cygnus|
|Mean Variability Period in Days||13.700|
|Variable Magnitude Range (Brighter - Dimmer)||6.333 - 6.388|
|Luminosity (x the Sun)||180,000.0000000|
|Calculated Effective Temperature||6,276 Kelvin|