We carried out high-sensitivity spectro-polarimetric observations of the central star of the Red Rectangle protoplanetary nebula with the aim of constraining the mechanism that gives its biconical shape. The stellar light of the central binary system is linearly polarised since it is scattered on the dust particles of the nebula. Surprisingly, the linear polarisation in the continuum is aligned with one of the spikes of the biconical outflow. Also, the observed Balmer lines, as well as the Ca?ii K lines, are polarised. These observational constraints are used to confirm or reject current theoretical models for the shaping mechanism of the Red Rectangle. We propose that the observed polarisation is not very likely to be generated by a uniform biconical stellar wind. Also, the hypothesis of a precessing jet does not completely match observations since it requires a larger aperture jet than for the nebula.
展开▼
机译：我们对红色矩形原行星状星云的中央恒星进行了高灵敏度的光谱极化观测，目的是限制给出其双圆锥形状的机制。中央双星系统的星光是线性偏振的，因为它散射在星云的尘埃颗粒上。出人意料的是，连续体中的线性极化与双锥形流出的尖峰之一对齐。同样，观察到的巴尔默线以及Ca ii K线也被极化。这些观察约束条件用于确认或拒绝“红色矩形”成形机制的当前理论模型。我们提出，观测到的极化不太可能由均匀的双锥形恒星风产生。而且，进动射流的假设与观测值不完全匹配，因为它需要比星云更大的孔径射流。
展开▼
