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A symmetric bipolar nebula around MWC 922
1Physics Department, University of Sydney, NSW 2006, Australia. p.tuthill@physics.usyd.edu.au
Science (New York, N.Y.)
|April 14, 2007
Summary
Infrared imaging reveals a regular, symmetric structure around the dust-enshrouded Be star MWC 922, forming a "Red Square" nebula. This structure, with its distinct features, suggests minimal disruption from chaotic effects.
Area of Science:
- Astronomy and Astrophysics
- Stellar Evolution
- Nebular Physics
Background:
- Be stars are rapidly rotating B-type stars with circumstellar disks.
- Dust-enshrouded stars present challenges for detailed structural analysis.
- MWC 922 is a peculiar Be star with an unusual surrounding nebula.
Purpose of the Study:
- To investigate the detailed structure of the nebula surrounding the Be star MWC 922.
- To analyze the morphology and symmetry of the dust-enshrouded object.
- To understand the formation mechanisms of the observed structures.
Main Methods:
- Infrared imaging of MWC 922.
- Morphological analysis of the nebular structure.
- Comparison with known astrophysical phenomena.
Main Results:
- Discovery of a highly regular and symmetric structure around MWC 922, dubbed the "Red Square" nebula.
- Observation of biconical lobes with nearly square aspects, crossed by rungs and terminating in bright knots.
- Identification of an equatorial dark band forming twin hyperbolic arcs and a linear comb structure.
- Nested polar rings observed, comparable to the system around Supernova 1987A.
Conclusions:
- The intricate, well-defined structures suggest minimal global turbulent or chaotic influence.
- The linear comb structure may indicate periodic features within the inner circumstellar disk.
- The observed morphology provides insights into the late stages of Be star evolution and mass ejection processes.
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