Universe Guide

66 Pegasi

66 Pegasi Facts

  • 66 Pegasi is a giant star that can be located in the constellation of Pegasus. The description is based on the spectral class.
  • 66 Pegasi is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (K3III) of the star, the star's colour is orange to red .
  • 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 388.29 light years away from us. Distance

66 Pegasi's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR8893. HIP115444 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD220363.

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 66 Pegasi. The Flamsteed name can be shortened to 66 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+11 4993.

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

Location of 66 Pegasi

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 66 Pegasi, the location is 23h 23m 04.56 and +12° 18` 50.2 .

Radial Velocity and Proper Motion of 66 Pegasi

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 -19.41 ± 0.24 milliarcseconds/year towards the north and 19.14 ± 0.27 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 -3.90000 km/s with an error of about 0.25 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 66 Pegasi

66 Pegasi Temperature and Colour

Based on the star's spectral type of K3III , 66 Pegasi's colour and type is orange to red giant star. The star has a B-V Colour Index of 1.31 which means the star's temperature is about 4,306 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

66 Pegasi 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 225.30 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

66 Pegasi Radius

66 Pegasi estimated radius has been calculated as being 16.32 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 11,356,361.02.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 19.17600798718061437098023972. 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.

66 Pegasi Iron Abundance

66 Pegasi Iron Abundance is 0.08 with an error value of 0.06 Fe/H with the Sun has a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

66 Pegasi Apparent and Absolute Magnitudes

66 Pegasi has an apparent magnitude of 5.09 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 0.06 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.29. 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 66 Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 9.88000 which gave the calculated distance to 66 Pegasi as 330.12 light years away from Earth or 101.21 parsecs. If you want that in miles, it is about 1,940,651,808,195,373.33, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 8.40000 which put 66 Pegasi at a distance of 388.29 light years or 119.05 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.

Using the 2007 distance, the star is roughly 24,555,654.08 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 7,403.00 Parsecs or 24,145.87 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 66 Pegasi

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 A380736353,795,829.99
Speed of Sound (Mach 1)767.269339,377,364.23
Concorde (Mach 2)1,534.54169,688,460.96
New Horizons Probe33,0007,890,719.12
Speed of Light670,616,629.00388.29

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 66 Pegasi Facts and Figures

Visual Facts

Primary / Proper / Traditional Name66 Pegasi
Alternative NamesHD 220363, HIP 115444, HR 8893, 66 Peg, BD+11 4993
Spectral TypeK3III
Constellation's Main StarNo
Multiple Star SystemYes
Star TypeGiant Star
ColourOrange to Red
GalaxyMilky Way
Absolute Magnitude 0.06 / -0.29
Visual / Apparent Magnitude5.09
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)23h 23m 04.56
Declination (Dec.)+12° 18` 50.2
Galactic Latitude-45.10779216 degrees
Galactic Longitude91.56018120 degrees
1997 Distance from Earth9.88000 Parallax (milliarcseconds)
 330.12 Light Years
 101.21 Parsecs
2007 Distance from Earth8.40000 Parallax (milliarcseconds)
 388.29 Light Years
 119.05 Parsecs
 24,555,654.08 Astronomical Units
Galacto-Centric Distance24,145.87 Light Years / 7,403.00 Parsecs
Proper Motion Dec. -19.41000 ± 0.24000 milliarcseconds/year
Proper Motion RA.19.14000 ± 0.27000 milliarcseconds/year
B-V Index1.31
Radial Velocity-3.90000 ± 0.25 km/s
Iron Abundance0.0800 ± 0.06 Fe/H
Semi-Major Axis7583.0000000
Stellar Luminosity (Lsun)225.3000000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)19.18
Effective Temperature4,306 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
220363+11 4993.0A6.1000024.00000-10.00000K0Orange

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