SCYON Abstract

Received on February 27 2010

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

AuthorsJulia I. Arias (1), Rodolfo H. Barbá (1,2), Roberto C. Gamen (3), Nidia I. Morrell (4), Jesús Maíz Appellániz (5), Emilio J. Alfaro (5), Nolan R. Walborn (6), and Christian Moni Bidin (7)
Affiliation(1) Departamento de Física, Universidad de La Serena, Benavente 980, La Serena, Chile
(2) Instituto de Ciencias Astronómicas de la Tierra, y del Espacio (ICATE-CONICET), Av. Espanja 1512 Sur, J5402DSP, San Juan, Argentina
(3) Instituto de Astrofísica de La Plata, CONICET; Facultad de Cs Astronómicas y Geofísicas, Universidad Nac. de La Plata, Paseo del Bosque S/N, La Plata, Argentina
(4) Las Campanas Observatory, The Carnegie Observatories, Casilla 601, La Serena, Chile
(5) Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, Granada 18008, Spain
(6) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
(7) Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
Accepted byAstrophysical Journal Letters, Vol. 710, 30 (Feb. 2010)
Contactjulia@dfuls.cl
URL
Links

Abstract

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 O9V and B0.5V, is characterized by a period of 1.5415±0.0006 days. With a spectral type O7.5V, 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.