This glyph Metoro explains as toga, a word I have connected in my mind with Tonga, the island in the south, thinking that toga means south.

But in the Rapanui language it seems to mean (among other things) winter (while summer = hora). Another meaning - which I guess that Metoro had in mind - is 'to lean against something, to hold something fast; support, post supporting the roof.'

And then we are back again to the pillars supporting heaven. I imagine that there is a pillar or post (toga) in the south (toga) which would be close by in winter (toga).

There are 10 supporting pillars according to Tahitian mythology. Why none of them Sirius?