Universe Guide


121 Tauri - HD36819 - HIP26248

121 Tauri is a blue subgiant star that can be located in the constellation of Taurus. HIP26248 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD36819. 121 Tauri has alternative name(s), 121 Tauri , 121 Tau.

Location of 121 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 121 Tauri, the location is 05h 35m 27.12 and +24d02`22.7 .

Proper Motion of 121 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 -019.67 ± 000.13 towards the north and 015.52 ± 000.22 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 121 Tauri

121 Tauri has a spectral type of B2.5IV. This means the star is a blue coloured subgiant star. The star has a B-V Colour Index of -0.09 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 11,375 Kelvin.

121 Tauri has been calculated as 3.72 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,591,160.69.km.

121 Tauri Apparent and Absolute Magnitudes

121 Tauri has an apparent magnitude of 5.37 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 -0.95 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.78. 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 121 Tauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 5.44 which gave the calculated distance to 121 Tauri as 599.56 light years away from Earth or 183.82 parsecs. In 2007, Hipparcos data was revised with a new parallax of 5.90 which put 121 Tauri at a distance of 552.82 light years or 169.49 parsecs.

It would take a spaceship travelling at the speed of light, 599.56 years using the 1997 distance to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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121 Tauri Facts

Alternative Names

Traditional Name121 Tauri
Short Name121 Tau
Alternative Name(s)121 Tauri
Hipparcos Library I.D.26248
Bonner DurchmusterungBD+23 954
Henry Draper Designation36819

Visual Facts

Star Typesubgiant star
Absolute Magnitude-0.95 / -0.78
Apparent Magnitude5.37
Right Ascension (R.A.)05h 35m 27.12
Declination (Dec.)+24d02`22.7
1997 Distance from Earth5.44 Parallax (milliarcseconds)
 599.56 Light Years
 183.82 Parsecs
2007 Distance from Earth5.90 Parallax (milliarcseconds)
 552.82 Light Years
 169.49 Parsecs
Proper Motion Dec.-19.67 ± 0.13 milliarcseconds/year
Proper Motion RA.15.52 ± 0.22 milliarcseconds/year
B-V Index-0.09
Spectral TypeB2.5IV
Colour(B) blue

Estimated Facts

Radius (x the Sun)3.72
Calculated Effective Temperature11,375 Kelvin

Sources and Links

SIMBAD SourceLink

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