Universe Guide


40 Draconis, HD166865, HIP88127

40 Draconis is a orange to red main sequence dwarf star that can be located in the constellation of Draco. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. The star has an estimated age of 3.40 Billion of Years but could be as young as 2.80 to 4.10 according to Hipparcos.

HIP88127 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD166865.

Location of 40 Draconis

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 40 Draconis, the location is 18h 00m 03.37 and +80d00`01.9 .

Proper Motion of 40 Draconis

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 120.37 ± 6.91 miliarcseconds/year towards the north and 47.06 ± 6.19 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Radius) of 40 Draconis

40 Draconis has a spectral type of K2Vvar. This means the star is a orange to red main sequence dwarf star. The star is 7416.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24188.2735910400000000s. The star has a B-V Colour Index of 0.52 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,202 Kelvin.

40 Draconis Radius has been calculated as being 2.46 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,715,137.64.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.53. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -0.05 with an error value of 0.08 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 3.40 Billion years old but could be between 2.80 and 4.10 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

40 Draconis Apparent and Absolute Magnitudes

40 Draconis has an apparent magnitude of 6.11 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 2.58 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.80. 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 40 Draconis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 19.64 which gave the calculated distance to 40 Draconis as 166.07 light years away from Earth or 50.92 parsecs. It would take a spaceship travelling at the speed of light, 166.07 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 13.77 which put 40 Draconis at a distance of 236.87 light years or 72.62 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 7,416.00 Parsecs or 24,188.27 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

40 Draconis Facts

Alternative Names

Traditional/Proper Name40 Draconis
Flamsteed Name40 Draconis
Flamsteed Short Name40 Dra
Hipparcos Library I.D.88127
Bonner DurchmusterungBD+79 570
Henry Draper Designation166865

Visual Facts

Star Typemain sequence dwarf star
Age3.40 Billion Years Old
Age Range2.80 - 4.10 Billion Years Old
Absolute Magnitude2.58 / 1.80
Visual / Apparent Magnitude6.11
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)18h 00m 03.37
Declination (Dec.)+80d00`01.9
Galactic Latitude28.91 degrees
Galactic Longitude111.78 degrees
1997 Distance from Earth19.64 Parallax (milliarcseconds)
 166.07 Light Years
 50.92 Parsecs
2007 Revised Distance from Earth13.77 Parallax (milliarcseconds)
 236.87 Light Years
 72.62 Parsecs
Galacto-Centric Distance24,188.27 Light Years / 7,416.00 Parsecs
Proper Motion Dec.120.37 ± 6.91 milliarcseconds/year
Proper Motion RA.47.06 ± 6.19 milliarcseconds/year
B-V Index0.52
Radial Velocity5.76 ± 0.07 km/s
Iron Abundance-0.05 ± 0.08 Fe/H
Spectral TypeK2Vvar
Colour(K) Orange to Red

Estimated Facts

Calculated Effective Temperature6,202 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
166865+79 570.0B6.2000046.00000127.00000F5Yellow/White1984
+79 574.0C9.20000-15.0000021.00000G5Yellow1984

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