Abstract
THE Wolf–Rayet star AS431 (number 147 in ref. 1) is known to be bright at X-ray and radio wavelengths2,3, and previous radio-interferometric observations indicate that it has an extended struc-ture3. Here we report new interferometric observations of AS431 using MERLIN (the Jodrell Multi-Element Radio Linked Inter-ferometer Network), in which the sensitivity was sufficient to map the stellar thermal-continuum radio emission with a beam size of 0.1 arcsec. The object is resolved into two radio sources, separated by 0.6 arcsec, corresponding to a spatial separation of 1,100 AU at the assumed distance of 1.9 kpc. The computed brightness of the two sources, ∼10,000 K, is typical of optically thick thermal emission from a stellar wind, but compared with other observations2suggests that some part of the emission is non-thermal. One of the radio components corresponds to the position of the single source revealed by accurate optical observations. We simulate the observed total radio spectrum with a two-component model for the emission.
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Moran, J., Davis, R., Bode, M. et al. MERLIN observations of the Wolf–Rayet star AS431 (WR147)-a double radio source. Nature 340, 449–450 (1989). https://doi.org/10.1038/340449a0
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DOI: https://doi.org/10.1038/340449a0
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