O7.5III Walborn71 standard: xi Per - O7.5III((f)) Walborn73 standard: xi Per - O7.5III(n)((f)) # Primary standard xi Per = HD 24912 (J0358+3547; V=4.0) *O7.5III(n)((f)): Walborn73 O7.5III((f)): Walborn71 O7.5III(f): Bisiachi76 O7.5III: Bisiachi82 O7.5III(f): Mathys89 O7.5I: Conti71 O7.5: Lesh68 O7III: Garrison77(standard) O7I: Herrero92 O7: : Voroshilov85 O7: MK43,Berger55 O8III: Williams36 O9: Cannon