Linear polarization in forbidden lines of the T Tauri star RY Tauri

We performed high-dispersion spectropolarimetry for the T Tauri star RY Tauri and measured linear polarization in seven forbidden lines of [OI]lambda lambda 5577, 6300, 6364, [NII]lambda 6583, [SII]lambda lambda 6716, 6731, and [FeII]lambda 7155. This is the first high-dispersion spectropolarimetry for forbidden lines in T Tauri stars. We successfully detected intrinsic polarization in the [OI]lambda 6300 line. The intrinsic [OI]lambda 6300 polarization corrected for the foreground polarization was derived as p([OI]) = 1.17 +/- 0.54% and theta([OI]) = 107 degrees +/- 13 degrees, whereas the polarization of the nearby continuum was p(cont) = 2.4-3.1% and theta(cont) = 2 degrees-11 degrees. The position angle of [OI]lambda 6300 polarization is compared with the circumstellar structures found by previous studies. It is nearly perpendicular to the disk long-axis and parallel to the optical H alpha jet. Both the perpendicularity and parallelism potentially suggest relatively axisymmetric distribution of the [OI]lambda 6300 emitting region and surrounding scattering medium. We constructed a simplified scattering model composed of a point source on a jet axis as an [OI]lambda 6300 emitter and a flat disk with an inner hole as a scatterer. Applying the observed polarization to the model suggests that the [OI]lambda 6300 emission emerges close to the central star with a possible separation of less than a few x 0.1 AU.