Gamma Draconis
Sign in to saveAlso known as Eltanin, Etamin
star in the northern constellation of Draco
Astronomical data · SIMBAD
- Object type
- *
- Spectral type
- K5III
- Distance
- 154 light-years
- Redshift
- z = -0.00009309340577867697
- Coordinates
- RA 269.1515° · Dec 51.4889°
via SIMBAD · CDS Strasbourg
Key facts
- Constellation
- Draco
- Right ascension
- 17 56 36.36988
- Declination
- +51 ° 29 ′ 20.0242 ″
- Spectral type
- K5 III
- U b color index
- +1.87
- B v color index
- +1.52
via Wikipedia infobox
~4 min read
Encyclopedic overview
Gamma Draconis, formally named Eltanin /ɛlˈteɪnɪn/, is a star in the northern constellation of Draco. Contrary to its gamma-designation (historically third-ranked), it is the brightest object in Draco at magnitude 2.2, outshining Beta Draconis by nearly half a magnitude and Alpha Draconis by over a magnitude.
Gamma Draconis is at a distance of 154.3 light-years (47.3 parsecs) from the Sun, as determined by parallax measurements from the Hipparcos astrometry satellite. In 1728, while unsuccessfully attempting to measure the star's parallax, James Bradley discovered the aberration of light resulting from the relative movement of the Earth. Bradley's discovery confirmed Copernicus' theory that the Earth revolved around the Sun. It is drifting closer to the Solar System with a radial velocity of about –28 km/s.
Excerpted from Wikipedia’s “Gamma Draconis” article, available under the CC BY-SA 4.0 licence.