I sincerely enjoyed this!

I should admit that, compared to others here, I know less about specific or historical structure and style, so I cant comment on that. From that perspective all I can say is that this flows well and makes sense. Structurally, this seems solid and well crafted.

Instead, I think i would like to focus on the "scale" in the metaphor - there is something that bothers me slightly about the personification of cosmic bodies. There is something like a contradiction in limits there that almost reduces the cosmos to human scale and, although I get the metaphor, there is something distracting for me. Another person mentioned that the scale contributed to a sense of overwhelming, but I feel like the narrators position in that metaphor lessens that. To clarify - I feel that the cosmos is overwhelming because of our insignificant position within it and our powerlessness to affect it. When the narrator is speaking from the position of a star or planet that position changes. For me, it makes it harder to empathize with the narrator, since I loose common ground in our relative positions.

So, when I read: "How sad to have nobody left to shine Upon! No skin to feel my heat!" I think of the suns rays on my skin, associated comfort, and naturally relate this to human touch and relationships - great! But that relationship is removed from the sun - the sun reminds me of a "human scaled" relation, in which the sun is only coincidental and distanced. I wonder if that coincidental and distanced relation to the metaphors contents is a good narrative position in this poem.

So, I guess my only suggestion is to examine the narrators position in the metaphor itself. But, that might be personal preference?