Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 1B009
The Orion Bullets: New GEMS MCAO images
Ginsburg, Adam (University of Colorado, Boulder / ESO)
Bally, John (University of Colorado, Boulder)
Youngblood, Allison (University of Colorado, Boulder)
Abstract:
The Orion A molecular cloud (OMC1) is the nearest site of massive star
formation at a distance of 414 pc. The BN/KL region within it contains signs
of a massive explosion triggered ~500 years ago by decay of a non-
hierarchical multiple system of massive stars. We present observations of the
OMC1 core at high spatial resolution (<0.1\") in narrow-band [Fe II] 1.64um and
H2 S(1) 1-0 2.12um filters. The new data reveal compact (0.1\" to 0.5\") knots
with unique excitation and chemical properties, unveiling new details about
the three-dimensional structure of the explosion. Bright H2 emission from
these compact, high proper-motion knots and compact [Fe II] features are
consistent with scenario proposed by Bally et al. (2011) in which they are
interpreted to be high density (n > 10^8 cm^{-3}) disk fragments launched from
within a few AU of a massive star by a > three-body dynamical interaction that
led to the ejection of the BN objects and the formation of a compact
(separation < few AU) binary, most likely radio source I. The proper motions
are as high as 400 km/s, hinting at the enormous energy unleashed in the
explosion. The data also unveiled a population of obscured close binary
systems. This new population will allow a comparison of embedded young binary
systems with the older, un-obscured, visual binary population to test models
of the evolution of multiplicity statistics in the Orion Nebula Cluster.
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