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The Three-dimensional Structure of the Eta Carinae HomunculusWe investigate, using the modeling code SHAPE, the three-dimensional structure of the bipolar Homunculus nebula surrounding Eta Carinae as mapped by new ESO VLT/X-Shooter observations of the H2 (lambda) = 2.12125 micrometers emission line. Our results reveal for the first time important deviations from the axisymmetric bipolar morphology: 1) circumpolar trenches in each lobe positioned point-symmetrically from the center and 2) offplanar protrusions in the equatorial region from each lobe at longitudinal (approximately 55 degrees) and latitudinal (10 degrees to 20 degrees) distances from the projected apastron direction of the binary orbit. The angular distance between the protrusions (approximately 110 degrees) is similar to the angular extent of each polar trench (approximately 130 degrees) and nearly equal to the opening angle of the wind-wind collision cavity (approximately 110 degrees). As in previous studies, we confirm a hole near the centre of each polar lobe and no detectable near-IR H2 emission from the thin optical skirt seen prominently in visible imagery. We conclude that the interaction between the outflows and/or radiation from the central binary stars and their orientation in space has had, and possibly still has, a strong influence on the Homunculus. This implies that prevailing theoretical models of the Homunculus are incomplete as most assume a single star origin that produces an axisymmetric nebula.We discuss how the newly found features might be related to the Homunculus ejection, the central binary and the interacting stellar winds.
Document ID
20140017176
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Steffen, W. (Universidad Nacional Autonoma de Mexico Ensenada, Mexico)
Teodoro, M.
Madura, T.I. (Oak Ridge Associated Universities Greenbelt, MD, United States)
Groh, J.H. (Geneva Observatory Sauverny, Switzerland)
Gull, T.R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mehner, A. (European Southern Observatory Santiago, Chile)
Corcoran, M.F. (Universities Space Research Association Boulder, CO, United States)
Damineli, A. (Sao Paulo Univ. Brazil)
Hamaguchi, K. (Maryland Univ. Baltimore County Catonsville, MD, United States)
Date Acquired
December 9, 2014
Publication Date
May 29, 2014
Publication Information
Publisher: Royal Astronomical Society
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN15459
Funding Number(s)
CONTRACT_GRANT: NNG06EO90A
CONTRACT_GRANT: UNAMPAPIIT-IN101014
CONTRACT_GRANT: CNPq/MCTBrazil-201978/2012-1
CONTRACT_GRANT: NNH06CC03B
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
bipolar Homunculus nebula
projected apastron direction
three-dimensional structure

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