Science Highlights - Aluminum Oxide around a High-Mass Protostar Candidate

Aluminum Oxide around a High-Mass Protostar Candidate - Possible Link to the Solar System First Solids

Spatially resolved distributions of aluminum monoxide (AlO) emission lines at 497 (left) and 650 (right) GHz were found, based on subarcsecond observations obtained by ALMA, in the rotating outflow of Orion Source I, a candidate high-mass young stellar object, for the first time in star-forming regions. High-temperature metal-bearing gas is potentially a good probe to trace the kinematics and dynamics of circumstellar disks. Moreover, AlO is a key molecule in the formation of Solar System’s oldest rocks, Ca- and Al-rich inclusions (CAIs). It has been under debate where and how CAIs formed in the earliest epoch of Solar System. The limited distribution of AlO to the launching point of the outflow of Orion Source I indicates that AlO in the outflow could recondense into dust due to its refractory nature. Further observations of high-temperature metal-bearing molecules in the disk around YSOs could link the high-temperature CAI formation event occurred in the early Solar System to the star formation and subsequent planetary formation processes.

The results are published here