Universe Guide

Rho Coronae Borealis (15 Coronae Borealis) Star Facts

Rho Coronae Borealis Facts

Rho Coronae Borealis's Alternative Names

Rho Coronae Borealis (Rho Crb) is the Bayer Classification for the star. The Bayer Classification was created by Johann Bayer in the early nineteenth century. The brightest star in the constellation is normally given the Alpha designation although there are exceptions such as Pollux which is Beta Geminorum.

The Id of the star in the Yale Bright Star Catalogue is HR5968. HIP78459 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD143761. The Gliese ID of the star is GL 606.2. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Star Names

Rho Coronae Borealis has alternative name(s) :- , Rho Crb.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 15 Coronae Borealis with it shortened to 15 Crb.

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+33 2663.

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

Location of Rho Coronae Borealis

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 Rho Coronae Borealis, the location is 16h 01m 02.80 and +33° 18` 19.4 .

Radial Velocity and Proper Motion of Rho Coronae Borealis

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 -773.02 ± 0.19 milliarcseconds/year towards the north and -196.63 ± 0.28 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 17.75 km/s with an error of about 0.08 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.

Rho Coronae Borealis 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 1.89 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature, Age, Mass) of Rho Coronae Borealis

Rho Coronae Borealis Colour and Temperature

Rho Coronae Borealis has a spectral type of G2V. This means the star is a yellow main sequence star. The star has a B-V Colour Index of 0.61 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,859 Kelvin.

Rho Coronae Borealis Radius

Radius has been calculated as being 1.32 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 919,813.54.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 1.30. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 0.89 times that of the Sun's. 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.

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.

The stars age according to Hipparcos data files put the star at an age of about 10.40 Billion years old but could be between 8.50 and 11.70 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

Rho Coronae Borealis Apparent and Absolute Magnitudes

Rho Coronae Borealis has an apparent magnitude of 5.39 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 4.18 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.21. 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 Rho Coronae Borealis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 57.38 which gave the calculated distance to Rho Coronae Borealis as 56.84 light years away from Earth or 17.43 parsecs. If you want that in miles, it is 330,496,318,480,381.99.

In 2007, Hipparcos data was revised with a new parallax of 58.02 which put Rho Coronae Borealis at a distance of 56.22 light years or 17.24 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 3,555,980.48 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 7,393.00 Parsecs or 24,113.26 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Time to Travel to Rho Coronae Borealis

A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

If you were to drive there at about 120 m.p.h. in a car with an infinity engine so you didn't have to pull over for petrol, it would take you 2,784,508,885,097.97 hours or 317,866,311.08 years.

At the time of writing, the fastest probe so far created is the New Horizon probe which is travelling at a speed of 33,000 m.p.h. If the probe was travelling to Rho Coronae Borealis then it would take 10,125,486,854.90 hours / 1,155,877.49 years to get there. Speed Ref: N.A.S.A.

It would to take a spaceship journey travelling at the speed of light, 56.84 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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 Rho Coronae Borealis Facts and Figures

Visual Facts

Primary / Proper / Traditional NameRho Coronae Borealis
Alternative NamesRho Crb, HD 143761, HIP 78459, HR 5968, 15 Coronae Borealis, 15 Crb, BD+33 2663, Gliese 606.2, Rho Crb
Spectral TypeG2V
Constellation's Main StarNo
Multiple Star SystemYes
Star Type Main Sequence Dwarf Star
GalaxyMilky Way
ConstellationCorona Borealis
Age10.40 Billion Years Old
Age Range8.50 - 11.70 Billion Years Old
Absolute Magnitude 4.18 / 4.21
Visual / Apparent Magnitude5.39
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)16h 01m 02.80
Declination (Dec.)+33° 18` 19.4
Galactic Latitude48.92 degrees
Galactic Longitude53.49 degrees
1997 Distance from Earth57.38 Parallax (milliarcseconds)
 56.84 Light Years
 17.43 Parsecs
2007 Distance from Earth58.02 Parallax (milliarcseconds)
 56.22 Light Years
 17.24 Parsecs
 3,555,980.48 Astronomical Units
Galacto-Centric Distance24,113.26 Light Years / 7,393.00 Parsecs
Proper Motion Dec.-773.02 ± 0.19 milliarcseconds/year
Proper Motion RA.-196.63 ± 0.28 milliarcseconds/year
B-V Index0.61
Radial Velocity17.75 ± 0.08 km/s
Iron Abundance-0.22 ± 0.00 Fe/H
Semi-Major Axis6496.00
Stellar Luminosity (Lsun)1.89
Orbital Period (Days)78.00
Argument Of Periastron0.00

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count2

Estimated Calculated Facts

Radius (x the Sun)1.30
Effective Temperature5,859 Kelvin
Mass Compared to the Sun0.89

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
143761+33 2663.0A5.50000-190.00000-767.00000F8Yellow/White

List of Extrasolar Planets orbiting Rho Coronae Borealis

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
HD 143761 bConfirmed0.02439.8460.03720160.2196270.600
HD 143761 cConfirmed0.0063102.5400.0520160.4123190.000

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