ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Spectroscopic study of early-type multiple stellar systems. II. New binary subsystems
Autor/es:
VERAMENDI, M. E.; GONZÁLEZ, J.F.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2014 vol. 567 p. 1 - 10
ISSN:
0004-6361
Resumen:
Context. This work is part of a long-term spectroscopic study of a
sample of 30 multiple stars with early-type components. In this second
paper we present the results for six multiple systems in which new
stellar components have been detected. Aims: The main aim is to
increase the knowledge of stellar properties and dynamical structure of
early-type multiple stellar systems. Methods: Using spectroscopic
observations taken over a time baseline of more than five years we
measured radial velocities by cross-correlations and spectrally
separated the double-lined systems. In addition to the discovery of
objects with double-lined spectra, the existence of new spectroscopic
subsystems were inferred from the radial velocity variations of
single-lined components and through the variation of the barycentric
velocity of double-lined subsystems. Orbital elements were calculated
when possible. Results: Seven new stellar components and two
members that we expect to confirm with new observations have been
discovered in the six studied multiples. We present orbital parameters
for two double-lined binaries and preliminary orbits for three
single-lined spectroscopic binaries. Five of the six analysed systems
are quadruples, while the remaining has five components distributed on
four hierarchical levels. These multiplicity orders are in fact lower
limits, since these systems lack high-resolution visual observations and
additional hierarchical levels might exist in that separation range. Conclusions: The six analysed systems have a higher degree of
multiplicity and a more complex hierarchical structure than previously
known, which suggests that high-order multiple systems are significantly
more frequent than currently estimated. The long-term spectroscopic
monitoring of multiple systems has shown to be useful for the detection
of companions in intermediate hierarchical levels.