Sigma Ursae Majoris

The Bayer designation Sigma Ursae Majoris (σ UMa / σ Ursae Majoris) is shared by two star systems, σ¹ Ursae Majoris and σ² Ursae Majoris, in the constellation Ursa Major. They are separated by 0.33° on the sky.

σ¹ Ursae Majoris

Starbox short
name=σ¹ Ursae Majoris
epoch=J2000.0
constell=Ursa Major
ra=09^h 08^m 23.6^s
dec=+66° 52' 24"
spectral=K5III
appmag_v=+5.15
dist_ly=500 ± 45
dist_pc=153 ± 14
names=11 Ursae Majoris, HR 3609,
HD 77800, BD+67 573,
HIP 44857, SAO 14769,
GC 12576

Sigma-1 Ursae Majoris is an orange K-type giant with an apparent magnitude of +5.15. It is approximately 500 light years from Earth.

σ² Ursae Majoris

Starbox short
name=σ² Ursae Majoris
epoch=J2000.0
constell=Ursa Major
ra=09^h 10^m 23.2^s
dec=+67° 08' 05"
spectral=F7IV-V+K2V
appmag_v=4.85 + 8.16
dist_ly=66.7 ± 0.8
dist_pc=20.5 ± 0.3
names=13 Ursae Majoris, HR 3616,
HD 78154, BD+67 577,
HIP 45038, SAO 14788,
GC 12619, ADS 7203,
CCDM 09105+6707

Sigma-2 Ursae Majoris is a binary star approximately 66.7 light years from Earth. The primary component, Sigma-2 Ursae Majoris A, is a yellow-white F-type subgiant with an apparent magnitude of +4.85. The companion, Sigma-2 Ursae Majoris B, is an orange K-type main sequence dwarf with an apparent magnitude of +8.16. The two stars have a semi-major axis on the sky of 6 arcseconds and have an orbital period of 1067 years. There is a third component, Sigma-2 Ursae Majoris C, 205 arcseconds from the primary which is thought to be a line-of-sight co-incidence.