Tuban (α Dra / α Draconis / Dragon Alpha) is a 3rd-magnitude star in the constellation Dragon . Although Tuban has the designation "alpha", in terms of brightness among the stars of the Dragon, he takes only eighth place. The name of the star comes from the Arab. ثعبان - "snake".
| Tuban | |||
|---|---|---|---|
| Star | |||
| Observational data ( Age J2000.0 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 310 ± 20 St. years (95 ± 5 pc ) | ||
| Visible magnitude ( V ) | 3,647 | ||
| Constellation | The Dragon | ||
| Astrometry | |||
| Radial velocity ( R v ) | −13 km / s | ||
| Own movement (μ) | RA: −56.52 mas per year Dec: 17.19 mas per year | ||
| Parallax (π) | 10.56 ± 0.52 mas | ||
| Absolute magnitude (V) | 3,617 | ||
| Characteristics | |||
| Spectral class | A0III | ||
| Color Index ( B - V ) | −0.08 | ||
| Color Index ( U - B ) | −0.05 | ||
| Variability | no | ||
| physical characteristics | |||
| Weight | 3.85 M ☉ | ||
| Radius | 6,75 R ☉ | ||
| Temperature | 9950 ± 50 K | ||
| Luminosity | 300 [2] L ☉ | ||
| Metallicity | |||
| |||
| Database Information | |||
| SIMBAD | |||
About 5,000 years ago (between 3500-1500 BC), among the brightest stars, Tuban was closest to the north pole of the world and was polarisable of that time.
Notes
- ↑ 1 2 3 4 Gaia Data Release 2 - 2018.
- ↑ Professor James B. (Jim) Kaler. THUBAN (Alpha Draconis) . University of Illinois. Date of treatment December 16, 2010. Archived on April 28, 2013.
- ↑ The spectrum and a quantitative analysis of the Ap star alpha Draconis - 1970.