Universe GuideSearchTwitterComments

47 Aurigae

47 Aurigae Facts

47 Aurigae's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR2338. HIP30972 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD45466.

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 47 Aurigae with it shortened to 47 Aur.

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+46 1149.

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

Location of 47 Aurigae

The location of the 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 47 Aurigae, the location is 06h 30m 02.98 and +46° 41` 07.9 .

Radial Velocity and Proper Motion of 47 Aurigae

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 7.06 ± 0.20 miliarcseconds/year towards the north and -7.33 ± 0.34 miliarcseconds/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 -48.32 km/s with an error of about 0.20 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.

47 Aurigae 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 332.28 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) of 47 Aurigae

47 Aurigae Colour and Temperature

47 Aurigae has a spectral type of K4III. This means the star is a orange to red giant star. The star has a B-V Colour Index of 1.44 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,093 Kelvin.

47 Aurigae Radius

Radius has been calculated as being 20.18 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 14,038,028.12.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 23.16. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

47 Aurigae Apparent and Absolute Magnitudes

47 Aurigae has an apparent magnitude of 5.88 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 -0.18 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.48. 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 47 Aurigae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.15 which gave the calculated distance to 47 Aurigae as 530.35 light years away from Earth or 162.60 parsecs. It would take a spaceship travelling at the speed of light, 530.35 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 5.34 which put 47 Aurigae at a distance of 610.79 light years or 187.27 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 38,626,941.11 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 7,576.00 Parsecs or 24,710.13 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

Hide Explanations
Show GridLines

Additional 47 Aurigae Facts and Figures

Visual Facts


Primary / Proper / Traditional Name47 Aurigae
Alternative NamesHD 45466, HIP 30972, HR 2338, 47 Aur, BD+46 1149
Spectral TypeK4III
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeGiant Star
ColourOrange to Red
GalaxyMilky Way
ConstellationAuriga
Absolute Magnitude -0.18 / -0.48
Visual / Apparent Magnitude5.88
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)06h 30m 02.98
Declination (Dec.)+46° 41` 07.9
Galactic Latitude15.95 degrees
Galactic Longitude168.20 degrees
1997 Distance from Earth6.15 Parallax (milliarcseconds)
 530.35 Light Years
 162.60 Parsecs
2007 Distance from Earth5.34 Parallax (milliarcseconds)
 610.79 Light Years
 187.27 Parsecs
 38,626,941.11 Astronomical Units
Galacto-Centric Distance24,710.13 Light Years / 7,576.00 Parsecs
Proper Motion Dec.7.06 ± 0.20 milliarcseconds/year
Proper Motion RA.-7.33 ± 0.34 milliarcseconds/year
B-V Index1.44
Radial Velocity-48.32 ± 0.20 km/s
Eccentricity0.35
Semi-Major Axis9403.00
Stellar Luminosity (Lsun)332.28

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Estimated Calculated Facts


Radius (x the Sun)23.16
Effective Temperature4,093 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


Comments and Questions

There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.

   
x
This website is using cookies. More info. That's Fine