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21 Orionis

Bright yellow bright giant in Orion

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Proper Name	None
Bayer Designation	None
Flamsteed Number	21 Orionis
HR (BSC)	1746
HD	34658
Constellation	Orion
Right Ascension	5h 19m 11s
Declination	+2° 35' 45"
Distance	200 light years 61 parsecs
Magnitude	Apparent: +5.34 Absolute: +1.38
Spectral Class	F5II bright yellow bright giant
Optimum Visibility	December / January
Notes	Shining in the sky at fifth magnitude, 21 Orionis lies northwestward of Orion's Belt. This is a star belonging to the bright giant category, and is more than twenty times as luminous as the Sun. It has approximately twice the Sun's mass and twice its diameter.

The relatively bright star seen here to the east and south of 21 Orionis is seventh-magnitude HD 34745. An F-type star like 21 Orionis itself, HD 34745 is in the foreground of this image, considerably closer to the Solar System but also some ten times less luminous than 21 Orionis, and so it appears fainter as seen from Earth. Imagery provided by Aladin sky atlas

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