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Izar

HIP 72105; Epsilon Boo; 36 Boo

DoubleStar Boo Mag 2.70

Object Data

Catalog Designation
HIP 72105; Epsilon Boo; 36 Boo
Type
DoubleStar
Constellation
Boo
Magnitude
2.70
Right Ascension
14h 44m 59.2s
Declination
+27° 04' 27.0"
Distance
202 light-years
HR
5506
HIP
72105
Bayer
Epsilon
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About Izar

Description

Izar (also called Pulcherrima) is one of the most beautiful double stars in the sky at magnitude 2.70 in Bootes. A telescope reveals a stunning pair — a golden-orange giant (K0II-III, mag 2.5) and a blue-white companion (A2V, mag 4.6) separated by about 2.9 arcseconds. Located about 203 light-years from Earth.

Observing Tips

Izar lies in the waist of Bootes, about 10 degrees northeast of Arcturus. Resolving the close pair requires a 4-inch or larger telescope at 150x or more. The color contrast — warm orange and cool blue — is exquisite. Best observed April through August when Bootes is well-placed.

History

The name Izar comes from the Arabic 'al-izar,' meaning 'the girdle' or 'veil.' The celebrated astronomer Friedrich Georg Wilhelm Struve gave it the Latin name Pulcherrima, meaning 'the most beautiful,' after resolving the pair and being struck by its color contrast.

Fun Facts

Struve's nickname 'Pulcherrima' (most beautiful) has stuck for nearly 200 years, and Izar regularly appears on lists of the finest double stars. Its tight separation makes it a good test of telescope optics and atmospheric seeing.