Universe Guide


TY Mensae, HD37909, HIP25472

TY Mensae is a blue eclipsing main sequence dwarf star that can be located in the constellation of Mensa. TY Mensae is the brightest star in Mensa based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it.

HIP25472 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD37909.

TY Mensae has alternative name(s), TY Men.

Location of TY Mensae

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 TY Mensae, the location is 05h 26m 49.79 and -81d35`08.0 .

Proper Motion of TY Mensae

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 90.57 ± 0.51 miliarcseconds/year towards the north and -15.20 ± 0.56 miliarcseconds/year east if we saw them in the horizon.

TY Mensae 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 14.0000000 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 TY Mensae

TY Mensae has a spectral type of A3/A4V. This means the star is a blue main sequence dwarf star. The star is 7341.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23943.6510830400000000s. The star has a B-V Colour Index of 0.25 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,483 Kelvin.

TY Mensae Radius has been calculated as being 2.07 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,442,830.55.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.15. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

TY Mensae Apparent and Absolute Magnitudes

TY Mensae has an apparent magnitude of 8.27 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 2.14 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.06. 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 TY Mensae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 5.93 which gave the calculated distance to TY Mensae as 550.02 light years away from Earth or 168.63 parsecs. It would take a spaceship travelling at the speed of light, 550.02 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 5.73 which put TY Mensae at a distance of 569.22 light years or 174.52 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 7,341.00 Parsecs or 23,943.65 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 TY Mensae

The star is a eclipsing W Ursae Majoris/Contact Systems (subtype) 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. TY Mensae brightness ranges from a magnitude of 8.648 to a magnitude of 8.124 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.5 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.

TY Mensae Facts

Alternative Names

Traditional/Proper NameTY Mensae
Short NameTY Men
Hipparcos Library I.D.25472
Henry Draper Designation37909

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude2.14 / 2.06
Visual / Apparent Magnitude8.27
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)05h 26m 49.79
Declination (Dec.)-81d35`08.0
Galactic Latitude-29.87 degrees
Galactic Longitude293.88 degrees
1997 Distance from Earth5.93 Parallax (milliarcseconds)
 550.02 Light Years
 168.63 Parsecs
2007 Revised Distance from Earth5.73 Parallax (milliarcseconds)
 569.22 Light Years
 174.52 Parsecs
Galacto-Centric Distance23,943.65 Light Years / 7,341.00 Parsecs
Proper Motion Dec.90.57 ± 0.51 milliarcseconds/year
Proper Motion RA.-15.20 ± 0.56 milliarcseconds/year
B-V Index0.25
Spectral TypeA3/A4V
Colour(A) blue

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeW Ursae Majoris/Contact Systems (subtype)
Mean Variability Period in Days0.462
Variable Magnitude Range (Brighter - Dimmer)8.124 - 8.648

Estimated Facts

Luminosity (x the Sun)14.0000000
Calculated Effective Temperature7,483 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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