Universe Guide

Iota Cancri B (Companion Star) Facts

Iota Cancri B Facts

  • Iota Cancri B is a luminous giant star that can be located in the constellation of Cancer. The description is based on the spectral class.
  • Iota Cancri B is a main star of the constellation outline.
  • Based on the spectral type (G8II...) of the star, the star's colour is yellow .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 279.01 light years away from us. Distance

Iota Cancri B's Alternative Names

(Iota Cancri B) is the Bayer Classification for the star. The Bayer Classification was created by Johann Bayer in 1603. The brightest star in the constellation is normally given the Alpha designation, there are exceptions such as Pollux which is Beta Geminorum.

The Id of the star in the Yale Bright Star Catalogue is HR3474. HIP43100 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD74738.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 48 Cnc B. The Flamsteed name can be shortened to 48 Cnc B.

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+29 1823.

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

Location of Iota Cancri B

The location of the luminous giant 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 Iota Cancri B, the location is 08h 46m 40.00 and +28° 45` 54.6 .

Radial Velocity and Proper Motion of Iota Cancri B

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 -46.36 ± 1.66 milliarcseconds/year towards the north and -22.74 ± 2.75 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 25.00000 km/s with an error of about 1.50 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 of Iota Cancri B

Iota Cancri B Colour and Temperature

Based on the star's spectral type of G8II... , Iota Cancri B's colour and type is yellow luminous giant star. The star has a B-V Colour Index of 0.05 which means the star's temperature is about 9,222 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

Iota Cancri B Radius

Iota Cancri B estimated radius has been calculated as being 1.02 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 710,739.41.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.5108951265904228861818527615. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

Iota Cancri B Apparent and Absolute Magnitudes

Iota Cancri B has an apparent magnitude of 6.58 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 2.77 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.92. 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 B

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 17.31000 which gave the calculated distance to Iota Cancri B as 188.42 light years away from Earth or 57.77 parsecs. If you want that in miles, it is about 1,107,650,592,815,255.80, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 11.69000 which put Iota Cancri B at a distance of 279.01 light years or 85.54 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 17,643,768.58 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 Iota Cancri B

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 A380736254,223,839.21
Speed of Sound (Mach 1)767.269243,863,293.91
Concorde (Mach 2)1,534.54121,931,488.04
New Horizons Probe33,0005,669,961.99
Speed of Light670,616,629.00279.01

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 Iota Cancri B Facts and Figures

Visual Facts

Primary / Proper / Traditional NameIota Cancri B
Alternative NamesHD 74738, HIP 43100, HR 3474, 48 Cnc B, 48 Cnc B, BD+29 1823
Spectral TypeG8II...
Constellation's Main StarYes
Multiple Star SystemYes
Star TypeLuminous Giant Star
GalaxyMilky Way
Absolute Magnitude 2.77 / 1.92
Visual / Apparent Magnitude6.58
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)08h 46m 40.00
Declination (Dec.)+28° 45` 54.6
Galactic Latitude36.53836127 degrees
Galactic Longitude195.87492289 degrees
1997 Distance from Earth17.31000 Parallax (milliarcseconds)
 188.42 Light Years
 57.77 Parsecs
2007 Distance from Earth11.69000 Parallax (milliarcseconds)
 279.01 Light Years
 85.54 Parsecs
 17,643,768.58 Astronomical Units
Proper Motion Dec.-46.36000 ± 1.66000 milliarcseconds/year
Proper Motion RA.-22.74000 ± 2.75000 milliarcseconds/year
B-V Index0.05
Radial Velocity25.00000 ± 1.50 km/s
Associated / Clustered StarsDecapoda

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)1.51
Effective Temperature9,222 Kelvin

Sources and Links

SIMBAD SourceLink

Cancer Main Stars

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