WISE J080822.18–644357.3 ( WISE J0808–6443 ) was recently identified as a new M dwarf debris disc system and a candidate member of the 45 Myr-old Carina association .
Given that the strength of its infrared excess ( L _ { IR } / L _ { \star } \simeq 0.1 ) appears to be more consistent with a young protoplanetary disc , we present the first optical spectra of the star and reassess its evolutionary and membership status .
We find WISE J0808 - 6443 to be a Li-rich M5 star with strong H \alpha emission ( -125 < \textrm { EW } < -65 Å over 4 epochs ) whose strength and broad width are consistent with accretion at a low level ( \sim 10 ^ { -10 } M _ { \odot } yr ^ { -1 } ) from its disc .
The spectral energy distribution of the star is consistent with a primordial disc and is well-fit using a two-temperature blackbody model with T _ { inner } \simeq 1100 K and T _ { outer } \simeq 240 K. All WISE multi-epoch photometry shows the system exhibits significant variability in the 3.4 \micron and 4.6 \micron bands .
We calculate an improved proper motion based on archival astrometry , and combined with a new radial velocity , the kinematics of the star are consistent with membership in Carina at a kinematic distance of 90 \pm 9 pc .
The spectroscopic and photometric data are consistent with WISE J0808 - 6443 being a \sim 0.1 M _ { \odot } Classical T-Tauri star and one of the oldest known accreting M-type stars .
These results provide further evidence that the upper limit on the lifetimes of gas-rich discs – and hence the timescales to form and evolve protoplanetary systems – around the lowest mass stars may be longer than previously recognised , or some mechanism may be responsible for regenerating short-lived discs at later stages of pre-main sequence evolution .