Bibcode
Januszewski, Helen; Castro, Norberto; Oey, Sally; Becker, Juliette; Kratter, Kaitlin M.; Mateo, Mario; Simón-Díaz, S.; Bjorkman, Jon E.; Bjorkman, Karen; Sigut, Aaron; Smullen, Rachel; M2FS Team
Referencia bibliográfica
American Astronomical Society, AAS Meeting #231, id.#434.06
Advertised on:
1
2018
Número de citas
0
Número de citas referidas
0
Descripción
Field OB stars are a crucial probe of star formation in extreme
conditions. Properties of massive stars formed in relative isolation can
distinguish between competing star formation theories, while the
statistics of runaway stars allow an indirect test of the densest
conditions in clusters. To address these questions, we have obtained
multi-epoch, spectroscopic observations for a spatially complete sample
of 48 OB field stars in the SMC Wing with the IMACS and M2FS
multi-object spectrographs at the Magellan Telescopes. The observations
span 3-6 epochs per star, with sampling frequency ranging from one day
to about one year. From these spectra, we have calculated the radial
velocities (RVs) and, in particular, the systemic velocities for
binaries. Thus, we present the intrinsic RV distribution largely
uncontaminated by binary motions. We estimate the runaway frequency,
corresponding to the high velocity stars in our sample, and we also
constrain the binary frequency. The binary frequency and fitted orbital
parameters also place important constraints on star formation theories,
as these properties drive the process of runaway ejection in clusters,
and we discuss these properties as derived from our sample. This unique
kinematic analysis of a high mass field star population thus provides a
new look at the processes governing formation and interaction of stars
in environments at extreme densities, from isolation to dense clusters.