Universe Guide


41 Tauri, HD25823, HIP19171

41 Tauri is a blue rotating star that can be located in the constellation of Taurus. 41 Tauri is the brightest star in Taurus 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.

HIP19171 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD25823.

41 Tauri has alternative name(s), GS Tau.

Location of 41 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 41 Tauri, the location is 04h 06m 36.40 and +27d36`00.1 .

Proper Motion of 41 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 -52.34 ± 0.21 miliarcseconds/year towards the north and 21.88 ± 0.36 miliarcseconds/year east if we saw them in the horizon.

41 Tauri 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 61000.0000000 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 41 Tauri

41 Tauri has a spectral type of B9p Si. This means the star is a blue star. The star is 7516.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24514.4369350400000000s. The star has a B-V Colour Index of -0.12 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 14,942 Kelvin.

41 Tauri Radius has been calculated as being 1.94 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,350,757.65.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.65. 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 0.43 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

41 Tauri Apparent and Absolute Magnitudes

41 Tauri has an apparent magnitude of 5.18 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 -0.72 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.37. 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 41 Tauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.60 which gave the calculated distance to 41 Tauri as 494.19 light years away from Earth or 151.52 parsecs. It would take a spaceship travelling at the speed of light, 494.19 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 7.76 which put 41 Tauri at a distance of 420.31 light years or 128.87 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 7,516.00 Parsecs or 24,514.44 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 41 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. 41 Tauri brightness ranges from a magnitude of 5.153 to a magnitude of 5.132 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 7.2 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.

41 Tauri Facts

Alternative Names

Traditional/Proper Name41 Tauri
Flamsteed Name41 Tauri
Flamsteed Short Name41 Tau
Short NameGS Tau
Hipparcos Library I.D.19171
Bonner DurchmusterungBD+27 633
Henry Draper Designation25823

Visual Facts

Star Type star
Absolute Magnitude-0.72 / -0.37
Visual / Apparent Magnitude5.18
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)04h 06m 36.40
Declination (Dec.)+27d36`00.1
Galactic Latitude-17.96 degrees
Galactic Longitude167.43 degrees
1997 Distance from Earth6.60 Parallax (milliarcseconds)
 494.19 Light Years
 151.52 Parsecs
2007 Revised Distance from Earth7.76 Parallax (milliarcseconds)
 420.31 Light Years
 128.87 Parsecs
Galacto-Centric Distance24,514.44 Light Years / 7,516.00 Parsecs
Proper Motion Dec.-52.34 ± 0.21 milliarcseconds/year
Proper Motion RA.21.88 ± 0.36 milliarcseconds/year
B-V Index-0.12
Radial Velocity2.30 ± 4.20 km/s
Iron Abundance0.43 ± 9.99 Fe/H
Spectral TypeB9p Si
Colour(B) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days7.230
Variable Magnitude Range (Brighter - Dimmer)5.132 - 5.153

Estimated Facts

Luminosity (x the Sun)61,000.0000000
Calculated Effective Temperature14,942 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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