Universe Guide


33 Tauri, HD24769, HIP18485

33 Tauri is a blue rotating subgiant star that can be located in the constellation of Taurus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP18485 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD24769.

33 Tauri has alternative name(s), V817 Tau.

Location of 33 Tauri

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 33 Tauri, the location is 03h 57m 03.80 and +23d10`32.1 .

Proper Motion of 33 Tauri

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 -17.83 ± 0.24 miliarcseconds/year towards the north and 8.33 ± 0.52 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 33 Tauri

33 Tauri has a spectral type of B9.5IV. This means the star is a blue subgiant star. The star is 7587.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24746.0129092800000000s. The star has a B-V Colour Index of 0.03 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,140 Kelvin.

33 Tauri Radius has been calculated as being 3.74 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,603,128.08.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.80. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

33 Tauri Apparent and Absolute Magnitudes

33 Tauri has an apparent magnitude of 6.05 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 -0.01 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.55. 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 33 Tauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.14 which gave the calculated distance to 33 Tauri as 531.21 light years away from Earth or 162.87 parsecs. It would take a spaceship travelling at the speed of light, 531.21 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 4.79 which put 33 Tauri at a distance of 680.93 light years or 208.77 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.

The star's Galacto-Centric Distance is 7,587.00 Parsecs or 24,746.01 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of 33 Tauri

The star is a rotating Alpha2 Canum Venaticorum 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. 33 Tauri brightness ranges from a magnitude of 6.083 to a magnitude of 6.043 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.5 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.

33 Tauri Facts

Alternative Names

Traditional/Proper Name33 Tauri
Flamsteed Name33 Tauri
Flamsteed Short Name33 Tau
Short NameV817 Tau
Hipparcos Library I.D.18485
Bonner DurchmusterungBD+22 607
Henry Draper Designation24769

Visual Facts

Star Typesubgiant star
Absolute Magnitude-0.01 / -0.55
Visual / Apparent Magnitude6.05
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)03h 57m 03.80
Declination (Dec.)+23d10`32.1
Galactic Latitude-22.63 degrees
Galactic Longitude169.10 degrees
1997 Distance from Earth6.14 Parallax (milliarcseconds)
 531.21 Light Years
 162.87 Parsecs
2007 Revised Distance from Earth4.79 Parallax (milliarcseconds)
 680.93 Light Years
 208.77 Parsecs
Galacto-Centric Distance24,746.01 Light Years / 7,587.00 Parsecs
Proper Motion Dec.-17.83 ± 0.24 milliarcseconds/year
Proper Motion RA.8.33 ± 0.52 milliarcseconds/year
B-V Index0.03
Radial Velocity25.00 ± 10.00 km/s
Spectral TypeB9.5IV
Colour(B) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days1.488
Variable Magnitude Range (Brighter - Dimmer)6.043 - 6.083

Estimated Facts

Calculated Effective Temperature9,140 Kelvin

Sources and Links

SIMBAD SourceLink

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