Young stars and Educational outreach -- Oral Presentation
Multiplicity Among Massive Stars
Nancy Remage Evans, SAO
Multiwavelength observations as exemplified by NASA's Great
Observatories have provided a far clearer picture of the frequency of
multiplicity in star systems. Cepheids (typically 5 Msun) are good
representatives of massive stars. It is frequently the case that a third
star is not apparent until the second star can be directly observed. As
an example, the spectra of hot secondaries in Cepheid systems can be
obtained in the satellite ultraviolet. In a number of ways (to be
illustrated) this has provided evidence of a third star. In a recent
compilation of the best studied ``binary'' Cepheid systems, 44 percent
are in fact triple systems.