Universe Guide

CR Geminorum (Carbon Star) Facts

CR Geminorum Facts

CR Geminorum's Alternative Names

HIP31349 is the reference name for the star in the Hipparcos Star Catalogue.

CR Geminorum has alternative name(s) :- CR Gem, CR Gem.

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+16 1194.

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

Location of CR Geminorum

The location of the Carbon 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 object is compared to the celestial equator and is expressed in degrees. For CR Geminorum, the location is 06h 34m 23.92 and +16° 04` 30.3 .

Radial Velocity and Proper Motion of CR Geminorum

Proper Motion

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 -2.88 ± 1.38 milliarcseconds/year towards the north and -4.00 ± 2.01 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 28.00 km/s with an error of about 25.00 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties (Colour, Temperature) of CR Geminorum

CR Geminorum Colour and Temperature

CR Geminorum has a spectral type of C8.3v. This means the star is a carbon red Carbon star. The star has a B-V Colour Index of 3 which means the star's temperature is about 0 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu at being .

CR Geminorum Apparent and Absolute Magnitudes

CR Geminorum has an apparent magnitude of 8.64 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 1.09 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.91. 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 CR Geminorum

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.09 which gave the calculated distance to CR Geminorum as 1055.54 light years away from Earth or 323.62 parsecs. If you want that in miles, it is 707,862,676,575.

In 2007, Hipparcos data was revised with a new parallax of 2.85 which put CR Geminorum at a distance of 1144.43 light years or 350.88 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.

Using the 2007 distance, the star is roughly 72,373,690.91 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

Travel Time to CR Geminorum

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A3807361,042,763,299.90
Speed of Sound (Mach 1)767.2691,000,266,906.03
Concorde (Mach 2)1,534.54500,132,801.18
New Horizons Probe33,00023,256,781.48
Speed of Light670,616,629.001,144.43

Variable Type of CR Geminorum

The star is a pulsating Semi-Regular Star w 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. CR Geminorum brightness ranges from a magnitude of 8.931 to a magnitude of 8.394 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 250.0 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.

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Additional CR Geminorum Facts and Figures

Visual Facts

Primary / Proper / Traditional NameCR Geminorum
Alternative NamesCR Gem, HIP 31349, BD+16 1194, CR Gem
Spectral TypeC8.3v
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeCarbon Star
GalaxyMilky Way
Absolute Magnitude 1.09 / 0.91
Visual / Apparent Magnitude8.64
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)06h 34m 23.92
Declination (Dec.)+16° 04` 30.3
Galactic Latitude3.60 degrees
Galactic Longitude196.70 degrees
1997 Distance from Earth3.09 Parallax (milliarcseconds)
 1055.54 Light Years
 323.62 Parsecs
2007 Distance from Earth2.85 Parallax (milliarcseconds)
 1144.43 Light Years
 350.88 Parsecs
 72,373,690.91 Astronomical Units
Proper Motion Dec.-2.88 ± 1.38 milliarcseconds/year
Proper Motion RA.-4.00 ± 2.01 milliarcseconds/year
B-V Index3.00
Radial Velocity28.00 ± 25.00 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemi-Regular Star w
Mean Variability Period in Days250.000
Variable Magnitude Range (Brighter - Dimmer)8.394 - 8.931

Sources and Links

SIMBAD SourceLink

Related Stars

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