Universe Guide


49 Cancri - HD74521 - HIP42917

49 Cancri is a blue rotating star that can be located in the constellation of Cancer. HIP42917 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD74521. 49 Cancri has alternative name(s), 49 Cancri , BI_Cnc, 49 Cnc.

Location of 49 Cancri

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 49 Cancri, the location is 08h 44m 45.04 and +10d04`54.2 .

Proper Motion of 49 Cancri

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 -018.42 ± 000.19 towards the north and -014.41 ± 000.34 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 49 Cancri

49 Cancri has a spectral type of A1p.... This means the star is a blue star. The star has a B-V Colour Index of -0.06 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,136 Kelvin.

49 Cancri has been calculated as 1.97 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,371,624.46.km.

49 Cancri Apparent and Absolute Magnitudes

49 Cancri has an apparent magnitude of 5.63 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 0.15 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.07. 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 49 Cancri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 8.00 which gave the calculated distance to 49 Cancri as 407.70 light years away from Earth or 125 parsecs. It would take a spaceship travelling at the speed of light, 407.70 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 7.71 which put 49 Cancri at a distance of 423.04 light years or 129.70 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 49 Cancri

The star is a rotating Alpha2 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. 49 Cancri brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 7.0 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

49 Cancri Facts

Alternative Names

Traditional Name49 Cancri
Short NameBI Cnc, 49 Cnc
Alternative Name(s)49 Cancri
Hipparcos Library I.D.42917
Bonner DurchmusterungBD+10 1864
Henry Draper Designation74521

Visual Facts

Star Type star
Absolute Magnitude0.15 / 0.07
Apparent Magnitude5.63
Right Ascension (R.A.)08h 44m 45.04
Declination (Dec.)+10d04`54.2
1997 Distance from Earth8.00 Parallax (milliarcseconds)
 407.70 Light Years
 125 Parsecs
2007 Revised Distance from Earth7.71 Parallax (milliarcseconds)
 423.04 Light Years
 129.70 Parsecs
Proper Motion Dec.-18.42 ± 0.19 milliarcseconds/year
Proper Motion RA.-14.41 ± 0.34 milliarcseconds/year
B-V Index-0.06
Spectral TypeA1p...
Colour(A) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days7.000

Estimated Facts

Radius (x the Sun)1.97
Calculated Effective Temperature12,136 Kelvin

Sources and Links

SIMBAD SourceLink

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