VV Cep stars

VV Cephei (HD208816) is the principal star of a class of massive eclipsing binary consisting of an M supergiant and a hot B type companion. Its optical spectrum is characterized by strong Balmer and [Fe II] emission line. The spectrum is of  very complex type: M2Ia-Iabep + B8:Ve (composite spectra, with a very cool star and a hot star together). A mass transfer exist between the two components. For VV Cephei, the orbital period is 7430 days (20.3 years). The date of the mid-point of the last eclipse is January 4, 1998. At the time of eclipse the H-alpha emission disappear progressively. The total duration of the eclipse is about 1100 - 1400 days.  VV Cep is also a semi-regular long-period variable (magnitude = 4.8 - 5.4). For more info, click here. Other members of VV Cep class: KN Cas, AZ Cas, KP Pup, W Cep, U Lac, Alpha Sco.

Observations of VV Cephei

VV Cep localisation:

VV Cep = HD 208816     R.A.(2000) = 21 h 56 m 39s       Dec.(2000) = 63° 37' 32"

Comparison of the 22/08/1999 and 10/09/1999 spectra of  VV Cep. Note the good correlation between this two spectra. The 10/09/1999 is artificialy translated verticaly of 0.2. The spectrum is very complex.

H-alpha profile of VV Cep.

Observations of Alpha Scorpii

A semi-regular pulsating star. Type M1.5Ib.

Position (J2000):    
R.A. = 16 h 29 m 24 s      Dec. = -26° 25' 55"