We present multi-epoch continuum observations of the Class 0 protostellar system IRAS 16293–2422 taken with the Very Large Array ( VLA ) at multiple wavelengths between 7 mm and 15 cm ( 41 GHz down to 2 GHz ) , as well as single-epoch Atacama Large Millimeter/submillimeter Array ( ALMA ) continuum observations covering the range from 0.4 to 1.3 mm ( 700 GHz down to 230 GHz ) .
The new VLA observations confirm that source A2 is a protostar driving episodic mass ejections , and reveal the complex relative motion between A2 and A1 .
The spectrum of component B can be described by a single power law ( S _ { \nu } \propto \nu ^ { 2.28 } ) over the entire range from 3 to 700 GHz ( 10 cm down to 0.4 mm ) , suggesting that the emission is entirely dominated by dust even at \lambda = 10 cm .
Finally , the size of source B appears to increase with frequency up to 41 GHz , remaining roughly constant ( at 0 \mbox { $ { } ^ { \prime \prime } \hskip { -7.6 pt } . $ } 39 \equiv 55 AU ) at higher frequencies .
We interpret this as evidence that source B is a dusty structure of finite size that becomes increasingly optically thick at higher frequencies until , in the millimeter regime , the source becomes entirely optically thick .
The lack of excess free-free emission at long wavelengths , combined with the absence of high-velocity molecular emission indicates that source B does not drive a powerful outflow , and might indicate that source B is at a particularly early stage of its evolution .