Radio observations of the planetary nebula around the OH/IR star OH 354.88-0.54 (V1018 Sco) |
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| Authors: | Martin Cohen Jessica M Chapman Rachel M Deacon † Robert J Sault Quentin A Parker Anne J Green |
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| Institution: | Radio Astronomy Laboratory, University of California, Berkeley, CA 94720, USA;Australia Telescope National Facility, PO Box 76, Epping, NSW 2121, Australia;School of Physics A28, University of Sydney, NSW 2006, Australia;Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia;Department of Physics, Macquarie University, Sydney, NSW 2109 Australia;Astrophysics Department, School of Physics, Sydney University, Sydney, NSW 2006, Australia |
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| Abstract: | We present radio observations of the unique, recently formed, planetary nebula (PN) associated with a very long-period OH/IR variable star V1018 Sco that is unequivocally still in its asymptotic giant branch phase. Two regions within the optical nebula are clearly detected in non-thermal radio continuum emission, with radio spectral indices comparable to those seen in colliding-wind Wolf–Rayet binaries. We suggest that these represent shocked interactions between the hot, fast stellar wind and the cold nebular shell that represents the PN's slow wind moving away from the central star. This same interface produces both synchrotron radio continuum and the optical PN emission. The fast wind is neither spherical in geometry nor aligned with any obvious optical or radio axis. We also report the detection of transient H2O maser emission in this nebula. |
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| Keywords: | masers radiation mechanisms: non-thermal stars: AGB and post-AGB planetary nebulae: general |
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