Extra-solar comets near young β Pic analogs

Studies of the evolutionary precursors of β Pic have demonstrated that high velocity, accreting gas features are routinely detectable when the viewing geometry is similar to the β Pic system. We present a first exploration of the composition of the accreting gas toward 4 nearby, UV-luminous Herbig Ae/Be stars viewed through their circumstellar dust disks. We find that in addition to refractory materials, plausibly interpreted as sublimates of silicate grains, the accreting gas features in these stars contain carbon, mildly refractory species such as Zn II, and volatiles. Overall, the composition of the accreting gas is consistent with detection of the gaseous comae of star-grazing planetesimals of either cometary or carbonaceous chondritic composition.