Mariposa

From Halopedia, the Halo wiki

The "Rings of Mariposa" were mentioned in the story Second Sunrise over New Mombassa in the Halo Graphic Novel.[1] It's therefore likely to be a gas giant. At some point in time "the 6th Battle Group outmaneuvered and escaped" what was presumably a Covenant fleet near the planet Mariposa.

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