NON-ZEEMAN CIRCULAR POLARIZATION OF MOLECULAR ROTATIONAL SPECTRAL LINES

We present measurements of circular polarization from rotational spectral lines of molecular species in Orion KL, most notably 12CO (J = 2 → 1), obtained at the Caltech Submillimeter Observatory with the Four-Stokes-Parameter Spectral Line Polarimeter. We find levels of polarization of up to 1%–2% in general; for 12CO (J = 2 → 1) this level is comparable to that of linear polarization also measured for that line. We present a physical model …