Abstract
Multi-epoch and multi-frequency VLA observations of the Orion Nebula show that the radio emission from the Trapezium star θ1A Orionis undergoes large flux density variations on a time scale of months. Between 1982 April and 1983 February the flux density increased from 3 to 74 mJy, however it remained constant over a period of eight hours at the latter epoch. The radio spectrum is flat (α = 0.0) at all observed epochs. In addition, the radio angular size was measured to be 0.21 (~ 1.6 × 1015 cm at the distance of the Orion Nebula) at the epochs of maximum and minimum flux density. Interpretation in terms of non-thermal radio emission is difficult because of both the flat spectrum and the large source size. We suggest that the radio emission from θ1A is the result of recurrent mass loss outbursts from the BO.5 underlying star.
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© 1985 D. Reidel Publishing Company
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Garay, G., Moran, J.M., Reid, M.J. (1985). Radio Emission from θ1A Orionis. In: Hjellming, R.M., Gibson, D.M. (eds) Radio Stars. Astrophysics and Space Science Library, vol 116. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-5420-5_20
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DOI: https://doi.org/10.1007/978-94-009-5420-5_20
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