Universe Guide

Mebsuta (Epsilon Geminorum, 27 Geminorum) Star Facts

Mebsuta Facts

  • Mebsuta is a star that can be located in the constellation of Gemini. The description is based on the spectral class.
  • Mebsuta is a main star of the constellation outline.
  • Based on the spectral type (A3mA6-A9) of the star, the star's colour is blue - white .
  • The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 844.98 light years away from us. Distance

Mebsuta's Alternative Names

Epsilon Geminorum (Eps Gem) is the Bayer Classification for the star. The Bayer Classification was created by Johann Bayer in 1603. The brightest star in the constellation is normally given the Alpha designation, there are exceptions such as Pollux which is Beta Geminorum.

The Id of the star in the Yale Bright Star Catalogue is HR2473. HIP32246 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD48329. In Arabic, it is known as Al-Mabsutah.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 27 Geminorum. The Flamsteed name can be shortened to 27 Gem.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+25 1406.

More details on objects' alternative names can be found at Star Names .

Location of Mebsuta

The location of the star in the night sky 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 object is compared to the celestial equator and is expressed in degrees. For Mebsuta, the location is 06h 43m 55.93 and +25° 07` 52.2 .

Radial Velocity and Proper Motion of Mebsuta

Proper Motion

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 -12.36 ± 0.09 milliarcseconds/year towards the north and -5.57 ± 0.17 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 7.77000 km/s with an error of about 0.23 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties of Mebsuta

Mebsuta Colour and Temperature

Based on the star's spectral type of A3mA6-A9 , Mebsuta's colour and type is blue - white star. The star has a B-V Colour Index of 1.37 which means the star's temperature is about 4,262 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

Mebsuta 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 7,564.95 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Mebsuta Radius

Mebsuta estimated radius has been calculated as being 115.80 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 80,575,253.81.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 108.57151134253295427747977835. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

Mebsuta Iron Abundance

Mebsuta Iron Abundance is 0.11 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

Mebsuta Apparent and Absolute Magnitudes

Mebsuta has an apparent magnitude of 3.06 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 -4.15 If you used the 2007 Parallax value, you would get an absolute magnitude of -4.01. 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 Mebsuta

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.61000 which gave the calculated distance to Mebsuta as 903.50 light years away from Earth or 277.01 parsecs. If you want that in miles, it is about 5,311,338,024,671,391.64, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 3.86000 which put Mebsuta at a distance of 844.98 light years or 259.07 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.

Using the 2007 distance, the star is roughly 53,436,651.00 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun. The star's Galacto-Centric Distance is 7,652.00 Parsecs or 24,958.02 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to Mebsuta

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A380736769,915,270.61
Speed of Sound (Mach 1)767.269738,538,425.47
Concorde (Mach 2)1,534.54369,268,731.46
New Horizons Probe33,00017,171,443.61
Speed of Light670,616,629.00844.98

Meteor Showers Radiating from near Mebsuta

The Epsilon Geminids Meteor Shower radiants from a point near this star. The meteor shower runs typically between Oct 14 - Oct 27 with a peak date of Oct 18. The speed of a meteor in the shower is 70 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 70.

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.

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Additional Mebsuta Facts and Figures

Visual Facts

Primary / Proper / Traditional NameMebsuta
Alternative NamesEpsilon Geminorum, Eps Gem, Al-Mabsutah, HD 48329, HIP 32246, HR 2473, 27 Geminorum, 27 Gem, BD+25 1406
Spectral TypeA3mA6-A9
Constellation's Main StarYes
Multiple Star SystemYes
Star TypeStar
GalaxyMilky Way
Absolute Magnitude -4.15 / -4.01
Visual / Apparent Magnitude3.06
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)06h 43m 55.93
Declination (Dec.)+25° 07` 52.2
Galactic Latitude9.62908585 degrees
Galactic Longitude189.53600523 degrees
1997 Distance from Earth3.61000 Parallax (milliarcseconds)
 903.50 Light Years
 277.01 Parsecs
2007 Distance from Earth3.86000 Parallax (milliarcseconds)
 844.98 Light Years
 259.07 Parsecs
 53,436,651.00 Astronomical Units
Galacto-Centric Distance24,958.02 Light Years / 7,652.00 Parsecs
Proper Motion Dec.-12.36000 ± 0.09000 milliarcseconds/year
Proper Motion RA.-5.57000 ± 0.17000 milliarcseconds/year
B-V Index1.37
Radial Velocity7.77000 ± 0.23 km/s
Iron Abundance0.1100 ± 9.99 Fe/H
Semi-Major Axis8169.0000000
Stellar Luminosity (Lsun)7564.9500000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)108.57
Effective Temperature4,262 Kelvin

Sources and Links

SIMBAD SourceLink

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
48329+25 1406.0A3.20000-4.00000-15.00000G5Yellow
262668+25 1407.0B9.20000-18.00000-25.00000K2Orange1825

Location of Mebsuta in Gemini

Mebsuta Location in Gemini

The map was generated using Night Vision, an awesome free application by Brian Simpson.

Gemini Main Stars

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