The nature of strings in the nebula around eta Carinae

eta Carinae is one of the most extreme cases of a Luminous Blue Variable st ar. A bipolar nebula of 17 " size surrounds the central object. Even furthe r out, a large amount of filamentary material extends to a distance of 30 " or about 0.3 pc. In this paper we present a detailed kinematic and morphol ogical analysis of some outer filaments in this nebula which we call string s. All strings are extremly long and narrow structures. We identified 5 str ings which have sizes of 0.058 to 0.177 pc in length and a width of only 0. 002 pc. Using high-resolution long-slit echelle spectroscopy it was found t hat the strings follow a Hubble law with velocities increasing towards larg er distances from the star. With these unique properties, high collimation and linear increase of the radial velocity the strings represent a newly fo und phenomena in the structure and evolution of nebulae around LBVs. Finall y, we show that morphologically similar strings can be found in the planeta ry nebula NGC 6543, a possible PN-counterpart to this phenomenon.