Beta Draconis
 Location of β Draconis (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Draco |
| Right ascension | 17h 30m 25.96170s |
| Declination | +52° 18′ 04.9993″ |
| Apparent magnitude (V) | 2.79 |
| Characteristics | |
| Spectral type | G2 II |
| U−B color index | +0.64 |
| B−V color index | +0.98 |
| R−I color index | +0.48 |
| Astrometry | |
| Radial velocity (Rv) | −20.0 ± 0.9 km/s |
| Proper motion (μ) |
RA: −15.89 mas/yr Dec.: +12.28 mas/yr |
| Parallax (π) | 8.58 ± 0.10mas |
| Distance | 380 ± 4 ly (117 ± 1 pc) |
| Absolute magnitude (MV) | –2.28 |
| Details | |
| Mass | 6.0 ± 0.2 M☉ |
| Radius | 40 R☉ |
| Luminosity | 1,000 L☉ |
| Surface gravity (log g) | 1.86 ± 0.04 cgs |
| Temperature | 5,160 ± 150 K |
| Rotational velocity (v sin i) | 13 km/s |
| Age | 65 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Draconis (β Draconis, abbreviated Beta Dra, β Dra), also named Rastaban, is a binary star and the third-brightest star in the northern circumpolar constellation of Draco. With an apparent visual magnitude of 2.79, it is bright enough to be easily seen with the naked eye. Based upon parallax measurements from the Hipparcos astrometry satellite, it lies at a distance of about 380 light-years (120 parsecs) from the Sun.
β Draconis (Latinised to Beta Draconis) is the system's Bayer designation. It also bears a double star designation of ADS 10611.
It bore the traditional name Rastaban, which has also been used for Gamma Draconis. This name, less commonly written Rastaben, derives from the Arabic phrase ra's ath-thu'ban "head of the serpent/dragon". It was also known as Asuia and Alwaid, the latter meaning "who is to be destroyed," though some trace it to Arabic al'awwad "the lute player". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Rastaban for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.
Beta Draconis is part of the asterism of the Mother Camels (Arabic al'awa'id), along with Gamma Draconis (Eltanin), Mu Draconis (Erakis), Nu Draconis (Kuma) and Xi Draconis (Grumium), which was later known as the Quinque Dromedarii.
...
Wikipedia