A-type star · white star
21 Her
21 Her is a white star in the constellation Hercules 366 ly from Earth. Its surface is about 9,906 K, about 1.7 times the Sun's surface temperature, and it shines at 51.19× the Sun's brightness. At magnitude 5.8 it is bright enough to see with the naked eye; the light you see left it 366 years ago.
Also catalogued as HR 6111 · HD 147869 · HIP 80351
9,906 K
temperature
5.83
apparent magnitude
51.19× ☉
luminosity vs Sun
A2sp...
spectral type
Distance & comparison with our Sun
366 years
at light speed from Earth
1.72×
as hot as the Sun
51.19×
the Sun's light output
0.58
absolute magnitude
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VISIBLE TO THE NAKED EYE
Star data from the HYG database v4.2 (Astronexus, CC BY-SA 4.0). Temperature and colour computed by gravityfinder from the B-V colour index; the illustration is generated from that temperature, not a photograph.