7 Draconis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 12h 47m 34.34473s |
| Declination | +66° 47′ 25.0977″ |
| Apparent magnitude (V) | 5.43 |
| Characteristics | |
| Spectral type | K5 III |
| B−V color index | 1.567±0.006 |
| Astrometry | |
| Radial velocity (Rv) | +11.33 km/s |
| Proper motion (μ) | RA: 6.674 mas/yr Dec.: −6.498 mas/yr |
| Parallax (π) | 4.1601±0.1056 mas |
| Distance | 780 ± 20 ly (240 ± 6 pc) |
| Absolute magnitude (MV) | −1.35 |
| Details | |
| Radius | 67 R☉ |
| Luminosity | 1,024.45 L☉ |
| Temperature | 3,945 K |
| Other designations | |
| Tianyi, 7 Dra, BD+67°764, FK5 3020, HD 111335, HIP 62423, HR 4863, SAO 15902 | |
| Database references | |
| SIMBAD | data |
7 Draconis, also named Tianyi /tiænˈjiː/, is a single star in the northern circumpolar constellation of Draco. It is visible to the naked eye as a faint orange-hued star with a stellar classification of 5.43. Based upon an annual parallax shift of 4.16 mas as seen from the Earth, the star is located approximately 780 light-years from the Sun.
This is an evolved giant star with a stellar classification of K5 III. The measured angular diameter of this star, after correction for limb darkening, is 2.61±0.03 mas. At its estimated distance, this yields a physical size of about 67 times the radius of the Sun. It is radiating about 1,024 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,945 K.