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arXiv · 1611.00855

ALMA band 8 continuum emission from Orion Source I

Tomoya Hirota·Masahiro N. Machida·Yuko Matsushita·Kazuhito Motogi·Naoko Matsumoto·Mi Kyoung Kim·Ross A. Burns·Mareki Honma
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Abstract

We have measured continuum flux densities of a high-mass protostar candidate, a radio source I in the Orion KL region (Orion Source I) using the Atacama Large Millimeter/Submillimeter Array (ALMA) at band 8 with an angular resolution of 0.1". The continuum emission at 430, 460, and 490 GHz associated with Source I shows an elongated structure along the northwest-southeast direction perpendicular to the so-called low-velocity bipolar outflow. The deconvolved size of the continuum source, 90 au times 20 au, is consistent with those reported previously at other millimeter/submillimeter wavelength. The flux density can be well fitted to the optically thick black-body spectral energy distribution (SED), and the brightness temperature is evaluated to be 700-800 K. It is much lower than that in the case of proton-electron or H- free-free radiations. Our data are consistent with the latest ALMA results by Plambeck & Wright (2016), in which the continuum emission have been proposed to arise from the edge-on circumstellar disk via thermal dust emission, unless the continuum source consists of an unresolved structure with the smaller beam filling factor.

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Tomoya Hirota, Masahiro N. Machida, Yuko Matsushita, Kazuhito Motogi, Naoko Matsumoto, Mi Kyoung Kim, Ross A. Burns, Mareki Honma. 2016-11-03. ALMA band 8 continuum emission from Orion Source I. https://doi.org/10.3847/1538-4357%2F833%2F2%2F238

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