2MASS J15460752-6258042: a mid-M dwarf hosting a prolonged accretion
  disc
  We report the discovery of the oldest (~55 Myr) mid-M type star known to host
on-going accretion. 2MASS J15460752-6258042 (2M1546, spectral type M5, 59.2 pc)
shows spectroscopic signs of accretion such as strong Ha, He I, and [O I]
emission lines, from which we estimate an accretion rate of ~10^-10 Msun/yr.
Considering the clearly detected infrared excess in all WISE bands, the shape
of its spectral energy distribution and its age, we believe the star is
surrounded by a transitional disc, clearly with some gas still present at inner
radii. The position and kinematics of the star from Gaia DR2 and our own radial
velocity measurements suggest membership in the nearby ~55 Myr-old Argus moving
group. At only 59pc from Earth, 2M1546 is one of the nearest accreting mid-M
dwarfs, making it an ideal target for studying the upper limit on the lifetimes
of gas-rich discs around low mass stars.
