The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɒ⟩.
It seems a "turned script a", being a rotated version of "script (cursive) a", which is the variant of a that lacks the extra stroke on top of a "printed a".
Latin turned alpha a ⟨ɒ⟩ has its linear stroke on the left, whereas Latin alpha a ⟨ɑ⟩ (for its unrounded counterpart) has its linear stroke on the right.
Symbols to the right in a cell are voiced, to the left are voiceless.
Shaded areas denote articulations judged impossible.