Simplify the following text for a Grade 8 native English-speaking person.
Original: A very small outward expansion to the Leverrier Ring has been named Lassell ; it is surrounded at its outer edge by the Arago Ring at 57,000 km .
Simplified: A faint outward extension to the Le Verrier Ring has been named Lassell ; it is bounded at its outer edge by the Arago Ring at 57000 km .