Universe Guide


Psi1 Aurigae, 46 Aurigae, HD44537, HIP30520

Psi1 Aurigae is a orange to red pulsating very luminous supergiant star that can be located in the constellation of Auriga. Psi1 Aurigae is the brightest star in Auriga based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Psi1 Aurigae is the Bayer Classification for the star. HIP30520 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD44537.

Psi1 Aurigae has alternative name(s), psi01 Aur.

Location of Psi1 Aurigae

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 Psi1 Aurigae, the location is 06h 24m 53.90 and +49d17`16.4 .

Proper Motion of Psi1 Aurigae

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 -1.82 ± 0.15 miliarcseconds/year towards the north and -0.66 ± 0.28 miliarcseconds/year east if we saw them in the horizon.

Psi1 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 20000.0000000 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 Psi1 Aurigae

Psi1 Aurigae has a spectral type of K5Iabvar. This means the star is a orange to red supergiant star. The star has a B-V Colour Index of 1.9 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 2,472 Kelvin.

Psi1 Aurigae Radius has been calculated as being 620.67 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 431,861,219.29.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 643.96. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.20 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Psi1 Aurigae Apparent and Absolute Magnitudes

Psi1 Aurigae has an apparent magnitude of 4.92 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 -5.43 If you used the 2007 Parallax value, you would get an absolute magnitude of -5.51. 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 Psi1 Aurigae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.85 which gave the calculated distance to Psi1 Aurigae as 3837.22 light years away from Earth or 1176.47 parsecs. It would take a spaceship travelling at the speed of light, 3837.22 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 0.82 which put Psi1 Aurigae at a distance of 3977.60 light years or 1219.51 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.

Variable Type of Psi1 Aurigae

The star is a pulsating Slow Irregular variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. Psi1 Aurigae brightness ranges from a magnitude of 5.288 to a magnitude of 4.848 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.4 days (variability).

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.

Psi1 Aurigae Facts

Alternative Names

Flamsteed Name46 Aurigae
Flamsteed Short Name46 Aur
Short Namepsi01 Aur
Bayer DesignationPsi1 Aurigae
Hipparcos Library I.D.30520
Bonner DurchmusterungBD+49 1488
Henry Draper Designation44537

Visual Facts

Star Typesupergiant star
Absolute Magnitude-5.43 / -5.51
Visual / Apparent Magnitude4.92
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)06h 24m 53.90
Declination (Dec.)+49d17`16.4
Galactic Latitude16.17 degrees
Galactic Longitude165.35 degrees
1997 Distance from Earth0.85 Parallax (milliarcseconds)
 3837.22 Light Years
 1176.47 Parsecs
2007 Revised Distance from Earth0.82 Parallax (milliarcseconds)
 3977.60 Light Years
 1219.51 Parsecs
Proper Motion Dec.-1.82 ± 0.15 milliarcseconds/year
Proper Motion RA.-0.66 ± 0.28 milliarcseconds/year
B-V Index1.90
Radial Velocity4.40 ± 0.39 km/s
Iron Abundance0.20 ± 9.99 Fe/H
Spectral TypeK5Iabvar
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSlow Irregular
Mean Variability Period in Days0.383
Variable Magnitude Range (Brighter - Dimmer)4.848 - 5.288

Estimated Facts

Luminosity (x the Sun)20,000.0000000
Calculated Effective Temperature2,472 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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