Universe Guide


UU Aurigae, HD46687, HIP31579

UU Aurigae is a pulsating luminous giant star that can be located in the constellation of Auriga. UU 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.

HIP31579 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD46687.

UU Aurigae has alternative name(s), UU Aur.

Location of UU 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 UU Aurigae, the location is 06h 36m 32.84 and +38d26`44.0 .

Proper Motion of UU 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 -19.90 ± 0.26 miliarcseconds/year towards the north and -0.50 ± 0.41 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Temperature, Radius) of UU Aurigae

UU Aurigae has a spectral type of C5II. This means the star is a luminous giant star. The star has a B-V Colour Index of 2.77 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 0 Kelvin. 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 -0.15 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

UU Aurigae Apparent and Absolute Magnitudes

UU Aurigae has an apparent magnitude of 5.40 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 -3.32 If you used the 2007 Parallax value, you would get an absolute magnitude of -6.70. 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 UU Aurigae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.80 which gave the calculated distance to UU Aurigae as 1812.02 light years away from Earth or 555.56 parsecs. It would take a spaceship travelling at the speed of light, 1812.02 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 0.38 which put UU Aurigae at a distance of 8583.25 light years or 2631.58 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 UU Aurigae

The star is a pulsating Semiregular late- (M, C, S or Me, Ce, Se) giants with poorly defined periodicity 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. UU Aurigae brightness ranges from a magnitude of 5.642 to a magnitude of 5.114 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 459.0 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.

UU Aurigae Facts

Alternative Names

Traditional/Proper NameUU Aurigae
Short NameUU Aur
Hipparcos Library I.D.31579
Bonner DurchmusterungBD+38 1539
Henry Draper Designation46687

Visual Facts

Star Typeluminous giant star
Absolute Magnitude-3.32 / -6.70
Visual / Apparent Magnitude5.40
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)06h 36m 32.84
Declination (Dec.)+38d26`44.0
Galactic Latitude13.78 degrees
Galactic Longitude176.52 degrees
1997 Distance from Earth1.80 Parallax (milliarcseconds)
 1812.02 Light Years
 555.56 Parsecs
2007 Revised Distance from Earth0.38 Parallax (milliarcseconds)
 8583.25 Light Years
 2631.58 Parsecs
Proper Motion Dec.-19.90 ± 0.26 milliarcseconds/year
Proper Motion RA.-0.50 ± 0.41 milliarcseconds/year
B-V Index2.77
Radial Velocity13.40 ± 0.80 km/s
Iron Abundance-0.15 ± 9.99 Fe/H
Spectral TypeC5II

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemiregular late- (M, C, S or Me, Ce, Se) giants with poorly defined periodicity
Mean Variability Period in Days459.000
Variable Magnitude Range (Brighter - Dimmer)5.114 - 5.642

Estimated Facts

Sources and Links

SIMBAD SourceLink

Related Stars

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
46687+38 1539.0A-22.00000-10.00000NA

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