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Elnath (Beta Tauri) - HD35497 - HIP25428 - HR1791

Elnath (Beta Tauri) is a blue giant star that can be located in the constellation of Taurus. It is the 28th brightest star in the night sky. Beta Tauri is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR1791. HIP25428 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD35497. Elnath has alternative name(s), Beta Tau,112 Tauri , 112 Tau.

Elnath or El Nath depending on how you like to spell it, is the closest major star to the anti-centre of the galaxy. If I was at the Galactic Centre and shone a really powerful laser at Earth and then continued onwards. El Nath would be the nearest major star to the laser line. There are closer stars but none as well known as El Nath.

Elnath is also part of the Aurigae constellation but for purposes of One Star to One Constellation, El Nath is associated with Taurus. Even when its being used in Auriga, its still known as Beta Tauri or Elnath.

Location of Elnath

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 Elnath, the location is 05h 26m 17.50 and +28d36`28.3 .

Proper Motion of Elnath

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 -173.58 ± 000.17 towards the north and 022.76 ± 000.34 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Elnath

Elnath has a spectral type of B7III. This means the star is a blue giant star. The star has a B-V Colour Index of -0.13 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,762 Kelvin.

Elnath has been calculated as 3.59 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,497,835.30.km.

Elnath Apparent and Absolute Magnitudes

Elnath has an apparent magnitude of 1.65 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 -1.37 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.42. 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 Elnath

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 24.89 which gave the calculated distance to Elnath as 131.04 light years away from Earth or 40.18 parsecs. It would take a spaceship travelling at the speed of light, 131.04 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 24.36 which put Elnath at a distance of 133.89 light years or 41.05 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.

Meteor Showers Radiating from near Elnath

The Daytime Beta Taurids Meteor Shower radiants from a point near this star. The meteor shower runs typically between 5 Jun- 17 Jul with a peak date of 28-Jun. The speed of a meteor in the shower is 27 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 27.

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.

Elnath Facts

Alternative Names

Traditional NameElnath
Short Name112 Tau
Bayer DesignationBeta Tauri
Alternative Name(s)Beta Tau,112 Tauri
Hipparcos Library I.D.25428
Yale Bright Star Catalogue (HR) Id1791
Bonner DurchmusterungBD+28 795
Henry Draper Designation35497

Visual Facts

Star Typegiant star
Absolute Magnitude-1.37 / -1.42
Apparent Magnitude1.65
Right Ascension (R.A.)05h 26m 17.50
Declination (Dec.)+28d36`28.3
1997 Distance from Earth24.89 Parallax (milliarcseconds)
 131.04 Light Years
 40.18 Parsecs
2007 Revised Distance from Earth24.36 Parallax (milliarcseconds)
 133.89 Light Years
 41.05 Parsecs
Proper Motion Dec.-173.58 ± 0.17 milliarcseconds/year
Proper Motion RA.22.76 ± 0.34 milliarcseconds/year
B-V Index-0.13
Spectral TypeB7III
Brightest in Night Sky28th
Colour(B) blue

Estimated Facts

Radius (x the Sun)3.59
Calculated Effective Temperature12,762 Kelvin

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
35497+28 795.0A1.8000025.00000-175.00000B8Blue/White
B1898

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