论文标题
2MASS J15460752-6258042：一个中间矮人，主持长时间的积聚光盘
2MASS J15460752-6258042: a mid-M dwarf hosting a prolonged accretion disc
论文作者
论文摘要
我们报告发现最古老的（〜55 Myr）Mid-M型星星已知持续积聚。 2MASS J15460752-6258042（2M1546，频谱M5，59.2 PC）显示了吸积的光谱迹象，例如强HA，He I和[O I]发射线，我们从中估算出〜10^-10 msun/yr的积分率。考虑到所有明智的频段中清晰检测到的红外过量，其光谱能量分布的形状和年龄，我们相信恒星被过渡盘包围，显然，内部半径仍然存在一些气体。 Gaia DR2和我们自己的径向速度测量值的恒星的位置和运动学表明，附近约55个Myr Eld Argus移动组的成员身份。在距地球的59％时，2M1546是最接近的Mid-m矮人之一，使其成为研究低质量恒星周围气体富含气体圆盘的上限的理想目标。
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.
