Luminosity of Vega
| Value | 1.536e28 W |
| Status | Measured: ± 2.00e+26 W (0.013 relative) |
| Source | Yoon et al. (2010), 40.12 ± 0.45 L⊙ apparent; true angle-averaged output ≈47 L⊙ |
| Categories | Astronomicalstellar |
| nanowatt | 1.5360000e+37 nW |
| erg per second | 1.5360000e+35 erg/s |
| microwatt | 1.5360000e+34 μW |
| milliwatt | 1.5360000e+31 mW |
| foot pound-force per minute | 6.7973728e+29 ft·lbf/min |
| BTU per hour | 5.2410495e+28 BTU/h |
| watt | 1.5360000e+28 W |
| kilocalorie per hour | 1.3207223e+28 kcal/h |
| foot pound-force per second | 1.1328955e+28 ft·lbf/s |
| thousand BTU per hour | 5.2410495e+25 MBH |
| metric horsepower | 2.0883788e+25 PS |
| horsepower (mechanical) | 2.0598099e+25 hp |
| electrical horsepower | 2.0589812e+25 hp (elec) |
| kilowatt | 1.5360000e+25 kW |
| ton of refrigeration | 4.3675413e+24 ton |
| boiler horsepower | 1.5658290e+24 bhp |
| million BTU per hour | 5.2410495e+22 MMBTU/h |
| megawatt | 1.5360000e+22 MW |
| gigawatt | 1.5360000e+19 GW |
| terawatt | 1.5360000e+16 TW |
| solar luminosity | 40.125392 Lsun |
Learning zone
Vega spent a century as astronomy's standard candle in the literal sense: the magnitude system was calibrated so that Vega defines magnitude zero at every wavelength, and "Vega magnitudes" remain a standard unit today. It was also the first star ever photographed (1850, at Harvard) and among the first with a measured parallax. So it stung when the standard star turned out to be lying. Interferometry confirmed in the 2000s that Vega spins at over 90 per cent of breakup, flattened and pole-brightened — and because we happen to view it nearly pole-on, we see its hottest face. The 40.12 L⊙ adopted here is the apparent luminosity inferred assuming isotropy; the true total output, averaged over viewing angles, is closer to 47 L⊙, and the difference is a standing lesson in how geometry contaminates even the most basic stellar quantities.
Vega's other bequest came from its infrared excess, discovered by IRAS in 1983: warm dust — a debris disk of colliding planetesimals, the first evidence of planet-forming material around another main-sequence star, now called the Vega phenomenon.