Detection of Aluminum Monoxide, AlO, and Aluminum Hydroxide, AlOH, toward VY CMa

The aluminum monoxide, AlO, radical, has been detected in three rotational transitions in the 2 and 1 mm regions belonging to N" = 3, 5, 6 with hyperfine structure probably somewhat resolved for the lowest transition:
E. D. Tenenbaum and L. M. Ziurys,
Millimeter Detection of AlO (X ²Σ⁺): Metal Oxide Chemistry in the Envelope of VY Canis Majoris
Astrophys. J. 694, L59–L63 (2009).
It appears as if only a very minute amount of Al is in the gas phase around O-rich circumstellar envelopes, in contrast to C-rich circumstellar envelopes, such as that of IRC +10216, in which more volatile molecules such as AlF, AlCl, and AlNC have been detected.

More recently, the same autors have detected aluminum hydroxide, AlOH, in the same source in three rotational transitions in the 2 and 1 mm regions belonging to J" = 4, 6, 8:
E. D. Tenenbaum and L. M. Ziurys,
Exotic Metal Molecules in Oxygen-rich Envelopes: Detection of AlOH (X ¹Σ⁺) in VY Canis Majoris
Astrophys. J. 712, L93–L63 (2010).
The molecule is approximately 17 times as abundant as AlO.