Terrible suffering of hero that shed light on the Somme? (4,5)

I believe the answer is:

star shell

This clue might be a double definition.

'terrible suffering of hero' is the first definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

'that shed light on the somme?' is the second definition.
(type of World War One projectile)

I've seen this clue in The Independent.

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