The status of the two possible companions is still not clarified.  One set of observations reports barely resolving two components, but there has not been confirmation of this.  Observations of Albireo assuming the spectrum is a composite of two stars derive a late B spectral type for the companion,  for example B8.  Adaptive optics measurements of the companion are best modelled by a B0V spectrum for the companion with an apparent magnitude of .  Different assumptions about the spectral type of the companion lead to wildly different physical properties, for example an effective temperature of either 12,000 K or 30,000 K.