Main Page | See live article | Alphabetical index

Ras Algethi

Ras Algethi (Arabic Rasalgethi from Ra`s al-Jathi a Head of the kneeling one) (α 1 Herculis | 64 Herculis) is a double star system with a primary massive red giant star and a closer companion.

Physical and other characteristics

Ras Algheti is the 4th largest star known to us, circa 720 times greater than the Sun.

Observation data
Semiregular Variable, type SR c  
Right ascension (RA, α) (J2000,00) 17 h 14 m 38.80 s
Declination (Dec, δ) (J2000,00) +14° 23' 25.0"
Distance from Earth 550 LY | (169 pc)
Visual brightness (V)  +3.1m to +3.9 | +5m to +7m
Absolute magnitude  
Physical characteristics
Mean Diameter (dS = 1,392,000 km) 560,000,000 km | ~ 402.3 dS
3.74 AU
Surface area  
Volume  
Mass  
Relative mass to the Sun
(mS = 1.9891 × 1030 kg)
 
Density  
Surface gravity  
Spectral type M5 Ib-II (Red Super Giant)
Surface temperature  
Age 
Color (B-V) (Orange-red | Bluish-green) 
V-I  
Luminosity (LS = 3.827 × 1026 J s-1)  
Orbital characteristics
Period of rotation 
Period