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arXiv · 1501.03362

Investigating the nature of the Fried Egg nebula: CO mm-line and optical spectroscopy of IRAS 17163-3907

Sofia H. J. Wallström·S. Muller·E. Lagadec·J. H. Black·R. D. Oudmaijer·K. Justtanont·H. van Winckel·A. A. Zijlstra
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Abstract

Through CO mm-line and optical spectroscopy, we investigate the properties of the Fried Egg nebula IRAS 17163-3907, which has recently been proposed to be one of the rare members of the yellow hypergiant class. The CO J=2-1 and J=3-2 emission arises from a region within 20" of the star and is clearly associated with the circumstellar material. The CO lines show a multi-component asymmetrical profile, and an unexpected velocity gradient is resolved in the east-west direction, suggesting a bipolar outflow. This is in contrast with the apparent symmetry of the dust envelope as observed in the infrared. The optical spectrum of IRAS 17163-3907 between 5100 and 9000 Å was compared with that of the archetypal yellow hypergiant IRC+10420 and was found to be very similar. These results build on previous evidence that IRAS 17163-3907 is a yellow hypergiant.

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Sofia H. J. Wallström, S. Muller, E. Lagadec, J. H. Black, R. D. Oudmaijer, K. Justtanont, H. van Winckel, A. A. Zijlstra. 2015-01-14. Investigating the nature of the Fried Egg nebula: CO mm-line and optical spectroscopy of IRAS 17163-3907. https://doi.org/10.1051/0004-6361%2F201321516

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