One of challenges for Season 4, Week 6 requires players to Search between a Playground, Campsite and a Footprint. The star is north-west of Greasy Grove, located at the bottom of B6 on the map. Here is the location on the map:

Search between a Playground, Campsite and a Footprint Battle Star Map Location

A close up on the map:

Search between a Playground, Campsite and a Footprint Battle Star Exact Location

Simply interact with the star to complete the challenge and receive 10 Battle Stars

Search between a Playground, Campsite and a Footprint Battle Star