1996A&A...310..228C

The pre-main sequence star TY CrA is an eclipsing multiple system; in addition to the spectroscopic signatures of the primary and the secondary, lines from a third component were recently detected. Here we present high resolution spectra of the Li I 6708A, [S II] 6716,6731A, and [O I] 6300A lines of the TY CrA system. [S II] and [O I] lines are undoubtedly detected in the visible spectrum of TY CrA. Their origin remains uncertain, but they might be due to the tertiary component. A long-term monitoring of the Li I lines of the tertiary component allows us to derive its orbital motion around the binary system. We propose a possible fit for the orbit of this third component, and estimate its dynamical and physical attributes. In particular, the orbit of the tertiary appears eccentric (e≃0.5) and highly inclined (∼70deg) with respect to the orbital plane of the close binary.