On The Multiplicity of the Zero-Age Main-Sequence O Star Herschel 36

Arias, J.I., Barbá, R.H., Gamen, R.C., Morrell, N.I., Maíz Apellániz, J., Alfaro, E.J., Sota, A., Walborn, N.R., Moni Bidin, C.
The Astrophysical Journal Letters, Volume 710, Issue 1, pp. L30-L34 (2010).


We present the analysis of high-resolution optical spectroscopic observations of the zero-age main-sequence O star Herschel 36 spanning six years. This star is definitely a multiple system, with at least three components detected in its spectrum. Based on our radial-velocity (RV) study, we propose a picture of a close massive binary and a more distant companion, most probably in wide orbit about each other. The orbital solution for the binary, whose components we identify as O9 V and B0.5 V, is characterized by a period of 1.5415 ± 0.0006 days. With a spectral type O7.5 V, the third body is the most luminous component of the system and also presents RV variations with a period close to 498 days. Some possible hypotheses to explain the variability are briefly addressed and further observations are suggested.