Theta Draconis
 Location of θ Draconis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Draco |
| Right ascension | 16h 01m 53.3457s |
| Declination | +58° 33′ 54.905″ |
| Apparent magnitude (V) | 4.1190 |
| Characteristics | |
| Spectral type | F9 V |
| U−B color index | +0.11 |
| B−V color index | +0.53 |
| Astrometry | |
| Radial velocity (Rv) | -8.5 km/s |
| Proper motion (μ) |
RA: -319.51 mas/yr Dec.: 334.97 mas/yr |
| Parallax (π) | 47.54 ± 0.12mas |
| Distance | 68.6 ± 0.2 ly (21.03 ± 0.05 pc) |
| Absolute magnitude (MV) | 2.50 |
| Details | |
| Mass | 1.21 M☉ |
| Radius | 2.5 R☉ |
| Luminosity | 8.7 L☉ |
| Surface gravity (log g) | 4.13 cgs |
| Temperature | 6,290 K |
| Metallicity [Fe/H] | +0.20 dex |
| Rotational velocity (v sin i) | 27 km/s |
| Age | 3.1 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Draconis (θ Dra / θ Draconis) is a fourth-magnitude star in the northern circumpolar constellation of Draco. Parallax measurements place it at an estimated distance of 68.6 light-years (21.0 parsecs) from Earth.
This star is 21% more massive than the Sun and has a radius 2.5 times the Sun's. It is radiating 8.7 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 6,290 K. This temperature is what gives it the yellow-white hue of an F-type main sequence star with a stellar classification of F9 V.
In Chinese, 紫微左垣 (Zǐ Wēi Zuǒ Yuán), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of θ Draconis, ι Draconis, η Draconis, ζ Draconis, υ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae. Consequently, θ Draconis itself is known as 紫微左垣二 (Zǐ Wēi Zuǒ Yuán èr, English: the Second Star of Left Wall of Purple Forbidden Enclosure.), representing 上宰 (Shǎngzǎi), meaning The First Premier. 上宰 (Shǎngzǎi) is westernized into Shang Tsae by R.H. Allen with meaning "the Minor Steward" but it was for η Dra (Aldibain)
Coordinates: 
16h 01m 53.35s, +58° 33′ 54.90″
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