Vega
Vega - the fifth-brightest star in the night sky, 25 light-years away in Lyra, and one of the most important stars in astronomy: for over a century it defined the zero point of the brightness scale. A hot blue-white A-type star twice the Sun's mass, spinning rapidly, it is ringed by a disk of dust - the first such 'debris disk' ever found, a possible sign of forming planets.
Key facts
Science
Physical
- Mass
- 4.25 × 10³⁰ kg · 2.13 M☉
- Radius
- 1,739,250 km · 2.5× wider than the Sun
- Density
- 193 kg/m³ · 0.19× water
- Spectral type
- A0V (blue-white main-sequence star)
Rotation
- Note
- Rotates about once every 16 hours; seen nearly pole-on.
Composition
- By mass
- A hot blue-white main-sequence star about 2.1 times the Sun's mass and ~40 times its light. It spins rapidly and is viewed nearly pole-on, so it looks hotter and brighter than its average surface.
Temperature
- Surface
- 9,600 K (9327 °C)
Radiation & temperature
- Luminosity
- 1.54 × 10²⁸ W · 40.1 L☉
- Surface temperature
- 9,600 K (9327 °C)
- Peak wavelength
- 302 nm · ultraviolet (invisible to the eye)
Discovery & history
- Method
- Naked-eye star
- Name
- Its IAU proper name Vega derives from the Arabic an-nasr al-waqi, 'the swooping eagle'. It is Alpha Lyrae, the brightest star of Lyra, the Lyre.
Vega was the first star ever photographed (1850) and the first to have its spectrum recorded. In 1983 the IRAS satellite discovered it radiating excess infrared light - warmth from a surrounding dust disk - launching the study of debris disks around other stars. Vega was Earth's pole star around 12,000 BC and will be again near 13,700 AD.
Images
Images from open archives · credit shown per image