B-type star · blue-white star

21 Per

21 Per is a blue-white star in the constellation Perseus 320 ly from Earth. Its surface is about 10,213 K, about 1.8 times the Sun's surface temperature, and it shines at 76.35× the Sun's brightness. At magnitude 5.1 it is bright enough to see with the naked eye; the light you see left it 320 years ago.

320 lybrightness mag 5.10B9p...

Also catalogued as HR 873 · HD 18296 · HIP 13775

10,213 K

temperature

5.10

apparent magnitude

76.35× ☉

luminosity vs Sun

B9p...

spectral type

Distance & comparison with our Sun

320 years

at light speed from Earth

1.77×

as hot as the Sun

76.35×

the Sun's light output

0.14

absolute magnitude

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21 PerB-type

Sky regionPerseusthis direction

Nearest stars

Bright stars in Perseus

Can you see it tonight?

VISIBLE TO THE NAKED EYE

Brightness mag 5.1To see it no equipment neededLook toward Perseus

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.