Resolving the MYSO binaries PDS 27 and PDS 37 with VLTI/PIONIER. (arXiv:1903.02667v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Koumpia_E/0/1/0/all/0/1">E. Koumpia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ababakr_K/0/1/0/all/0/1">K. M. Ababakr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wit_W/0/1/0/all/0/1">W. J. de Wit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oudmaijer_R/0/1/0/all/0/1">R. D. Oudmaijer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garatti_A/0/1/0/all/0/1">A. Caratti o Garatti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boley_P/0/1/0/all/0/1">P. Boley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Linz_H/0/1/0/all/0/1">H. Linz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kraus_S/0/1/0/all/0/1">S. Kraus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vink_J/0/1/0/all/0/1">J. S. Vink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouquin_J/0/1/0/all/0/1">J.-B Le Bouquin</a>
Binarity and multiplicity appear to be a common outcome in star formation. In
particular, the binary fraction of massive (OB-type) stars can be very high. In
many cases, the further stellar evolution of these stars is affected by binary
interactions at some stage during their lifetime. The origin of this high
binarity and the binary parameters are poorly understood because observational
constraints are scarce, which is predominantly due to a dearth of known young
massive binary systems. We aim to identify and describe massive young binary
systems in order to fill in the gaps of our knowledge of primordial binarity of
massive stars, which is crucial for our understanding of massive star
formation. We observed the two massive young stellar objects (MYSOs) PDS 27 and
PDS 37 at the highest spatial resolution provided by VLTI/PIONIER in the H-band
(1.3 mas). We applied geometrical models to fit the observed squared
visibilities and closure phases. In addition, we performed a radial velocity
analysis using published VLT/FORS2 spectropolarimetric and VLT/X-shooter
spectroscopic observations. Our findings suggest binary companions for both
objects at 12 mas (30 au) for PDS 27 and at 22-28 mas (42-54 au) for PDS 37.
This means that they are among the closest MYSO binaries resolved to date. Our
data spatially resolve PDS 27 and PDS 37 for the first time, revealing two of
the closest and most massive ($>$8 M$_odot$) YSO binary candidates to date.
PDS 27 and PDS 37 are rare but great laboratories to quantitatively inform and
test the theories on formation of such systems.
Binarity and multiplicity appear to be a common outcome in star formation. In
particular, the binary fraction of massive (OB-type) stars can be very high. In
many cases, the further stellar evolution of these stars is affected by binary
interactions at some stage during their lifetime. The origin of this high
binarity and the binary parameters are poorly understood because observational
constraints are scarce, which is predominantly due to a dearth of known young
massive binary systems. We aim to identify and describe massive young binary
systems in order to fill in the gaps of our knowledge of primordial binarity of
massive stars, which is crucial for our understanding of massive star
formation. We observed the two massive young stellar objects (MYSOs) PDS 27 and
PDS 37 at the highest spatial resolution provided by VLTI/PIONIER in the H-band
(1.3 mas). We applied geometrical models to fit the observed squared
visibilities and closure phases. In addition, we performed a radial velocity
analysis using published VLT/FORS2 spectropolarimetric and VLT/X-shooter
spectroscopic observations. Our findings suggest binary companions for both
objects at 12 mas (30 au) for PDS 27 and at 22-28 mas (42-54 au) for PDS 37.
This means that they are among the closest MYSO binaries resolved to date. Our
data spatially resolve PDS 27 and PDS 37 for the first time, revealing two of
the closest and most massive ($>$8 M$_odot$) YSO binary candidates to date.
PDS 27 and PDS 37 are rare but great laboratories to quantitatively inform and
test the theories on formation of such systems.
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