Thuban - α Draconis (alpha Draconis)

Thuban, also designated as α Draconis (alpha Draconis), is a variable hypergiant star in the constellation of Draco.

Thuban visual magnitude is 3.65. Because of its moderate brightness, Thuban should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about Thuban:

Color of Thuban ⬤

Magnitude of Thuban 3.65

Class Hypergiant

VISIBILITY RIGHT NOW Thuban - α Draconis (alpha Draconis) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 57°.

Celestial coordinates and finder chart of Thuban

Thuban is situated close to the northern celestial pole and, as such, it is visible for most part of the year from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Thuban are provided in the following table:

Right Ascension J2000 14h 04m 23s

Declination J2000 +64° 22’ 32”

Galactic Longitude 110.52°

Galactic Latitude 50.96°

Constellation Draco

The simplified sky map below shows the position of Thuban in the sky:

Finder chart Thuban - α Draconis (alpha Draconis) star

Simplified finder chart for Thuban - α Draconis (alpha Draconis).

Visibility of Thuban from your location

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Thuban - α Draconis (alpha Draconis) is circumpolar and transits at 01:43 UTC (altitude: 77.1°)

Digitized Sky Survey image of Thuban

The image below is a photograph of Thuban from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of Thuban is -0.055 arcsec per year in Right Ascension and 0.018 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Thuban - α Draconis (alpha Draconis) star

DSS2 image of Thuban. The red arrow shows the motion of Thuban during the next 10000 years (-9.17 arcmin in Right Ascension and 3.00 arcmin in declination);

Distance of Thuban from the Sun and relative movement

Thuban is distant 308.71 light years from the Sun and it is moving towards the Sun at the speed of 13 kilometers per second.

Distance (parsec) 94.70 pc

Distance (light year) 308.71 ly

Heliocentric radial velocity -13 km/s

Proper Motion RA -0.055 arcsec/year

Proper Motion Dec 0.018 arcsec/year

Spectral properties of Thuban

Thuban belongs to spectral class A0 and has a luminosity class of III corresponding to a hypergiant star.

Absolute magnitude -1.23

Spectral Type A0III

Color Index (B-V) -0.05

Temperature of Thuban 10795K

The red dot in the diagram below shows where Thuban is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of Thuban. Attribution: Richard Powell / CC BY-SA

Alternative designations of Thuban

Proper Name Thuban

Bayer designation α Draconis
(alpha Draconis)

Flamsteed designation 11 Draconis

Henry Draper Catalogue HD123299

SAO Catalogue SAO16273

Hipparcos Catalogue HIP68756

Durchmusterung Catalogue BD+65 978

FK5 Catalogue 521

General Catalogue of Variable Stars 6546

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Other stars in Draco