The Octans association is one of several young stellar moving groups recently discovered in the Solar neighbourhood and hence a valuable laboratory for studies of stellar , circumstellar disc and planetary evolution .
However , a lack of low-mass members or any members with trigonometric parallaxes means the age , distance and space motion of the group are poorly constrained .
To better determine its membership and age , we present the first spectroscopic survey for new K and M-type Octans members , resulting in the discovery of 29 UV-bright K5–M4 stars with kinematics , photometry and distances consistent with existing members .
Nine new members possess strong Li i \lambda 6708 absorption , which allow us to estimate a lithium age of 30–40 Myr , similar to that of the Tucana-Horologium association and bracketed by the firm lithium depletion boundary ages of the \beta Pictoris ( 20 Myr ) and Argus/IC 2391 ( 50 Myr ) associations .
Several stars also show hints in our medium-resolution spectra of fast rotation or spectroscopic binarity .
More so than other nearby associations , Octans is much larger than its age and internal velocity dispersion imply .
It may be the dispersing remnant of a sparse , extended structure which includes some younger members of the foreground Octans-Near association recently proposed by Zuckerman and collaborators .