Universe Guide


R Carinae, HD82901, HIP46806

R Carinae is a red pulsating star that can be located in the constellation of Carina. The star can not be seen by the naked eye, you need a telescope to see it.

HIP46806 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD82901.

R Carinae has alternative name(s), R Car.

Location of R Carinae

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 R Carinae, the location is 09h 32m 14.65 and -62d47`20.1 .

Proper Motion of R Carinae

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 17.74 ± 1.22 miliarcseconds/year towards the north and -36.22 ± 0.81 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of R Carinae

R Carinae has a spectral type of M6/M7pe. This means the star is a red star. The star is 7369.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24034.9768193600000000s. The star has a B-V Colour Index of 0.9 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,195 Kelvin.

R Carinae Radius has been calculated as being 4.81 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,343,474.95.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 5.94. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

R Carinae Apparent and Absolute Magnitudes

R Carinae has an apparent magnitude of 7.43 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 1.90 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.44. 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 R Carinae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.84 which gave the calculated distance to R Carinae as 416.02 light years away from Earth or 127.55 parsecs. It would take a spaceship travelling at the speed of light, 416.02 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 6.34 which put R Carinae at a distance of 514.45 light years or 157.73 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 7,369.00 Parsecs or 24,034.98 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 R Carinae

The star is a pulsating Omicron Ceti 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. R Carinae brightness ranges from a magnitude of 8.689 to a magnitude of 4.423 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 305.5 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.

R Carinae Facts

Alternative Names

Traditional/Proper NameR Carinae
Short NameR Car
Hipparcos Library I.D.46806
Henry Draper Designation82901

Visual Facts

Star Type star
Absolute Magnitude1.90 / 1.44
Visual / Apparent Magnitude7.43
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)09h 32m 14.65
Declination (Dec.)-62d47`20.1
Galactic Latitude-8.21 degrees
Galactic Longitude282.27 degrees
1997 Distance from Earth7.84 Parallax (milliarcseconds)
 416.02 Light Years
 127.55 Parsecs
2007 Revised Distance from Earth6.34 Parallax (milliarcseconds)
 514.45 Light Years
 157.73 Parsecs
Galacto-Centric Distance24,034.98 Light Years / 7,369.00 Parsecs
Proper Motion Dec.17.74 ± 1.22 milliarcseconds/year
Proper Motion RA.-36.22 ± 0.81 milliarcseconds/year
B-V Index0.90
Radial Velocity28.10 ± 1.00 km/s
Spectral TypeM6/M7pe
Colour(M) Red

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeOmicron Ceti
Mean Variability Period in Days305.500
Variable Magnitude Range (Brighter - Dimmer)4.423 - 8.689

Estimated Facts

Calculated Effective Temperature5,195 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.

Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
82901-62 1253.4A-33.0000015.00000M5Red

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