Step 2 - Set up smoothness and feather range
Make it a clear selection now by setting up smoothness and its feather.
Enter the menu Select > Modify > Smooth, and type 1 inside the dialogue box.
Enter the menu Select > Feather for 2 pixels feather radius.
Go the menu Select > Inverse and press Delete key after you duplicate your main object's layer.
The result of these sort actions will show like this: