Universe Guide

Markab (Alpha Pegasi, 54 Pegasi) Star Facts

Markab Facts

  • Markab is a giant star that can be located in the constellation of Pegasus. The description is based on the spectral class.
  • Markab is a main star of the constellation outline.
  • Based on the spectral type (B9.5III) of the star, the star's colour is blue .
  • Markab is the 90th brightest star in the night sky and the 3rd brightest star in Pegasus 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.
  • Markab has a radius that is 5.72 times bigger than the Suns. Radius
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 133.35 light years away from us. Distance

Information on Markab

Its name Markab is also shared with Tau Pegasi in the same constellation.

Markab's Alternative Names

Alpha Pegasi (Alf Peg) 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 HR8781. HIP113963 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD218045. In Arabic, it is known as Mankib al-Faras.

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 54 Pegasi. The Flamsteed name can be shortened to 54 Peg.

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+14 4926.

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

Location of Markab

The location of the giant 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 Markab, the location is 23h 04m 45.62 and +15° 12` 19.3 .

Radial Velocity and Proper Motion of Markab

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 -41.30 ± 0.11 milliarcseconds/year towards the north and 60.40 ± 0.19 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 -2.70000 km/s with an error of about 0.80 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 Markab

Markab Temperature and Colour

Based on the star's spectral type of B9.5III , Markab's colour and type is blue giant star. The star's effective temperature is 9,765 Kelvin which is hotter than our own Sun's effective Temperature which is 5,777 Kelvin.

Markab 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 170.85 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Markab Radius

Markab Radius has been calculated as being 5.72 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,979,976.00.km. If you need the diameter of the star, you just need to multiple the radius by 2.

Markab Apparent and Absolute Magnitudes

Markab has an apparent magnitude of 2.49 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 -0.67 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.57. 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 Markab

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 23.36000 which gave the calculated distance to Markab as 139.62 light years away from Earth or 42.81 parsecs. If you want that in miles, it is about 820,773,674,603,895.63, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 24.46000 which put Markab at a distance of 133.35 light years or 40.88 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 8,432,046.52 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 7,399.00 Parsecs or 24,132.83 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 Markab

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 A380736121,503,705.81
Speed of Sound (Mach 1)767.269116,551,988.26
Concorde (Mach 2)1,534.5458,275,918.18
New Horizons Probe33,0002,709,900.83
Speed of Light670,616,629.00133.35

Meteor Showers Radiating from near Markab

The Pegasids Meteor Shower radiants from a point near this star. The meteor shower runs typically between July 7-13 with a peak date of July 9th. 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 Markab Facts and Figures

Visual Facts

Primary / Proper / Traditional NameMarkab
Alternative NamesAlpha Pegasi, Alf Peg, Mankib al-Faras, HD 218045, HIP 113963, HR 8781, 54 Pegasi, 54 Peg, BD+14 4926
Spectral TypeB9.5III
Constellation's Main StarYes
Multiple Star SystemNo / Unknown
Star TypeGiant Star
GalaxyMilky Way
Absolute Magnitude -0.67 / -0.57
Visual / Apparent Magnitude2.49
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)23h 04m 45.62
Declination (Dec.)+15° 12` 19.3
Galactic Latitude-40.38090107 degrees
Galactic Longitude88.27968657 degrees
1997 Distance from Earth23.36000 Parallax (milliarcseconds)
 139.62 Light Years
 42.81 Parsecs
2007 Distance from Earth24.46000 Parallax (milliarcseconds)
 133.35 Light Years
 40.88 Parsecs
 8,432,046.52 Astronomical Units
Galacto-Centric Distance24,132.83 Light Years / 7,399.00 Parsecs
Proper Motion Dec.-41.30000 ± 0.11000 milliarcseconds/year
Proper Motion RA.60.40000 ± 0.19000 milliarcseconds/year
B-V Index0
Radial Velocity-2.70000 ± 0.80 km/s
Semi-Major Axis7720.0000000
Stellar Luminosity (Lsun)170.8500000
Brightest in Night Sky90th

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)5.72
Effective Temperature9,531 Kelvin

Sources and Links

SIMBAD SourceLink

Location of Markab in Pegasus

Markab Location in Pegasus

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

Pegasus Main Stars

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