AH Cep and CW Cep are both early B-type binaries with short orbital periods of 1.8 d and 2.7 d , respectively .
All four components are B0.5V types .
The binaries are also double-lined spectroscopic and eclipsing .
Consequently , solutions for orbital and stellar parameters make the pair of binaries ideal targets for a study of the colliding winds between two B stars . Chandra ACIS-I observations were obtained to determine X-ray luminosities .
AH Cep was detected with an unabsorbed X-ray luminosity at a 90 % confidence interval of ( 9 - 33 ) \times 10 ^ { 30 } erg s ^ { -1 } , or ( 0.5 - 1.7 ) \times 10 ^ { -7 } L _ { Bol } , relative to the combined Bolometric luminosities of the two components .
While formally consistent with expectations for embedded wind shocks , or binary wind collision , the near-twin system of CW Cep was a surprising non-detection .
For CW Cep , an upper limit was determined with L _ { X } / L _ { Bol } < 10 ^ { -8 } , again for the combined components .
One difference between these two systems is that AH Cep is part of a multiple system .
The X-rays from AH Cep may not arise from standard wind shocks nor wind collision , but perhaps instead from magnetism in any one of the four components of the system .
The possibility could be tested by searching for cyclic X-ray variability in AH Cep on the short orbital period of the inner B stars .