Universe Guide

Copernicus (Rho01 Cancri, 55 Cancri) Star Facts

Copernicus Facts

  • Copernicus is a main sequence star that can be located in the constellation of Cancer. The description is based on the spectral class.
  • Copernicus is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (G8V) of the star, the star's colour is yellow .
  • The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
  • It is calculated at being 10.200 Billion Years old. This information comes from ExoPlanet.
  • Copernicus has at least 5 Extrasolar Planets believed to be in orbit around the star.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 40.25 light years away from us. Distance

Copernicus's Alternative Names

Rho01 Cancri (Rho01 Cnc) 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 HR3522. HIP43587 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD75732. The Gliese ID of the star is GL 324A. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Star Names

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 55 Cancri. The Flamsteed name can be shortened to 55 Cnc.

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+28 1660.

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

Location of Copernicus

The location of the main sequence 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 Copernicus, the location is 08h 52m 36.13 and +28° 19` 53.0 .

Radial Velocity and Proper Motion of Copernicus

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 -234.05 ± 0.40 milliarcseconds/year towards the north and -485.80 ± 0.75 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 27.58000 km/s with an error of about 0.07 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 Copernicus

Copernicus Temperature and Colour

Based on the star's spectral type of G8V , Copernicus's colour and type is yellow main sequence star. The star's effective temperature is 5,235 Kelvin which is cooler than our own Sun's effective Temperature which is 5,777 Kelvin

Copernicus 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 0.66 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Copernicus Radius

Copernicus estimated radius has been calculated as being 0.95 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 659,536.63.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 0.9348764108632991073595061507. 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.

Copernicus Mass

The Copernicus's solar mass is 0.91 times that of our star, the Sun. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

Copernicus Metalicity

The star's metallicity is 0.310000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

Copernicus Estimated Age

The star is believed to be about 10.20 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.

Copernicus Apparent and Absolute Magnitudes

Copernicus has an apparent magnitude of 5.96 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 5.47 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.50. 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 Copernicus

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 79.80000 which gave the calculated distance to Copernicus as 40.87 light years away from Earth or 12.53 parsecs. If you want that in miles, it is about 240,259,419,002,014.14, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 81.03000 which put Copernicus at a distance of 40.25 light years or 12.34 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 2,545,289.97 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. The star's Galacto-Centric Distance is 7,409.00 Parsecs or 24,165.44 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to Copernicus

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 A38073636,674,346.90
Speed of Sound (Mach 1)767.26935,179,733.99
Concorde (Mach 2)1,534.5417,589,844.07
New Horizons Probe33,000817,949.07
Speed of Light670,616,629.0040.25

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 Copernicus Facts and Figures

Visual Facts

Primary / Proper / Traditional NameCopernicus
Alternative NamesRho01 Cancri, Rho01 Cnc, HD 75732, HIP 43587, HR 3522, 55 Cancri, 55 Cnc, BD+28 1660, Gliese 324A
Spectral TypeG8V
Constellation's Main StarNo
Multiple Star SystemYes
Star Type Main Sequence Dwarf Star
GalaxyMilky Way
Age10.20 Billion Years Old
Absolute Magnitude 5.47 / 5.50
Visual / Apparent Magnitude5.96
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)08h 52m 36.13
Declination (Dec.)+28° 19` 53.0
Galactic Latitude37.70017631 degrees
Galactic Longitude196.79430353 degrees
1997 Distance from Earth79.80000 Parallax (milliarcseconds)
 40.87 Light Years
 12.53 Parsecs
2007 Distance from Earth81.03000 Parallax (milliarcseconds)
 40.25 Light Years
 12.34 Parsecs
 2,545,289.97 Astronomical Units
Galacto-Centric Distance24,165.44 Light Years / 7,409.00 Parsecs
Proper Motion Dec.-234.05000 ± 0.40000 milliarcseconds/year
Proper Motion RA.-485.80000 ± 0.75000 milliarcseconds/year
B-V Index0.86
Radial Velocity27.58000 ± 0.07 km/s
Iron Abundance0.3500 ± 0.00 Fe/H
Semi-Major Axis7227.0000000
Stellar Luminosity (Lsun)0.6600000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count5

Estimated Calculated Facts

Radius (x the Sun)0.93
Effective Temperature5,141 Kelvin
Mass Compared to the Sun0.91

Sources and Links

SIMBAD SourceLink

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
75732+28 1660.0A6.00000-476.00000-227.00000G8Yellow

List of Extrasolar Planets orbiting Copernicus

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastronInclination
55 Cnc bConfirmed0.03114.6530.002319960.11339110.00089.730
55 Cnc cConfirmed0.007844.3730.07220020.23735356.000
55 Cnc dConfirmed0.154867.0000.026920025.446254.000
55 Cnc eConfirmed0.001350.7370.02820040.015439170.00090.360
55 Cnc fConfirmed0.0093260.9100.0820070.7733139.000

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