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Delta2 Lyrae

12 Lyrae

Proper NameNone
Bayer DesignationDelta2 Lyrae
Flamsteed Number12 Lyrae
HR (BSC)7139
Right Ascension18h 54m 30s
Declination+36° 53' 55"
Distance736 light years
226 parsecs
MagnitudeApparent: +4.3
Absolute: -2.5
Spectral ClassM4II red bright giant
Optimum VisibilityJuly
Notes This huge red giant star has a radius of approximately one Astronomical Unit so that, if it lay at the centre of the Solar System, its outer shell would extend as far as Earth's orbit. Delta2 Lyrae is a semiregular variable, and also probably a triple system (a binary pair of yellow dwarfs appear to be following a distant orbit around the red giant at the heart of the system).

Red Delta2 Lyrae forms a wide optical pair with Delta1 Lyrae, the blue star seen here to its northwest. Both stars are distant from the Sun, but they lie more than four hundred light years apart, and are not directly related to one another. Forming a backdrop to the pair is the open cluster Stephenson 1, which is more distant still at some 1,300 light years from the Solar System. Imagery provided by Aladin sky atlas


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