Universe Guide


Iota Cancri A (Iota Cancri B) - HD74739 - HIP43103

Iota Cancri A (Iota Cancri B) is a white to yellow very luminous supergiant star that can be located in the constellation of Cancer. Iota Cancri B is the Bayer Classification for the star. HIP43103 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD74739. Iota Cancri A has alternative name(s), 48 Cancri , 48 Cnc. Iota Cancri A is a multiple star system with 2 stars orbiting in its solar system.

Location of Iota Cancri A

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 Iota Cancri A, the location is 08h 46m 41.83 and +28d45`36.0 .

Proper Motion of Iota Cancri A

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 -045.69 ± 000.38 towards the north and -021.58 ± 000.61 east if we saw them in the horizon.

Iota Cancri A 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 11000.0000000 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 Iota Cancri A

Iota Cancri A has a spectral type of G8Iab:. This means the star is a white to yellow supergiant star. The star has a B-V Colour Index of 1 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,973 Kelvin.

Iota Cancri A has been calculated as 17.93 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 12,478,387.59.km.

The star has a companion star which is in orbit close by, it has at least the following companions in close orbit, Iota Cancri B.

Iota Cancri A Apparent and Absolute Magnitudes

Iota Cancri A has an apparent magnitude of 4.03 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 -0.77 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.00. 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 Iota Cancri A

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 10.94 which gave the calculated distance to Iota Cancri A as 298.14 light years away from Earth or 91.41 parsecs. It would take a spaceship travelling at the speed of light, 298.14 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 9.85 which put Iota Cancri A at a distance of 331.13 light years or 101.52 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.

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.

Iota Cancri A Facts

Alternative Names

Traditional NameIota Cancri A
Short Name48 Cnc
Bayer DesignationIota Cancri B
Alternative Name(s)48 Cancri
Hipparcos Library I.D.43103
Bonner DurchmusterungBD+29 1824
Henry Draper Designation74739

Visual Facts

Star Typesupergiant star
Absolute Magnitude-0.77 / -1.00
Apparent Magnitude4.03
Right Ascension (R.A.)08h 46m 41.83
Declination (Dec.)+28d45`36.0
1997 Distance from Earth10.94 Parallax (milliarcseconds)
 298.14 Light Years
 91.41 Parsecs
2007 Revised Distance from Earth9.85 Parallax (milliarcseconds)
 331.13 Light Years
 101.52 Parsecs
Proper Motion Dec.-45.69 ± 0.38 milliarcseconds/year
Proper Motion RA.-21.58 ± 0.61 milliarcseconds/year
B-V Index1.00
Spectral TypeG8Iab:
Colour(G) White to Yellow

Companions (Multi-Star and Exoplanets) Facts

Stars in Solar System2
Companion StarsIota Cancri B

Estimated Facts

Radius (x the Sun)17.93
Luminosity (x the Sun)11,000.0000000
Calculated Effective Temperature4,973 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Iota Cancri A in Cancer

Iota Cancri A (Iota Cancri B) Location in Cancer

The map was generated using Night Vision, an awesome free application by Brian Simpson.

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