The nature of strings in the nebula around Eta Carinae

Kerstin Weis, Wolfgang J. Duschl, You-Hua Chu

Published 1999-07-26Version 1

Eta Carinae is one of the most extreme cases of a Luminous Blue Variable star. A bipolar nebula of 17" size surrounds the central object. Even further 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 morphological analysis of some outer filaments in this nebula which we call strings. All strings are extremly long and narrow structures. We identified 5 strings 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 that the strings follow a Hubble law with velocities increasing towards larger distances from the star. With these unique properties, high collimation and linear increase of the radial velocity the strings represent a newly found phenomena in the structure and evolution of nebulae around LBVs. Finally, we show that morphologically similar strings can be found in the planetary nebula NGC 6543, a possible PN-counterpart to this phenomenon.