Cannot implicitly convert type IEnumerable<T> to IQueryable<T>

Obfuscated Scenario: A person has zero, one or many pets.

Using Linq to Sql, the need is to get an IQueryable list of pets for the given personID.
Here’s the poorly mangled/butchered/obfuscated portion of the ERD:

alt text

Code:

 public IQueryable<Pet> GetPersonPets(int personID)
    {
        var personPets= from p in Person
        where p.ID == somePersonID
        select p.Pets;

        return personPets; //fail
        // return (IQueryable<Pet>)personPets  //also fail
        // return personPets.AsQueryable<Pet>()  //also fail
    }

Exception Raised:

Cannot implicitly convert type 
'System.Collections.Generic.IEnumerable (System.Data.Linq.EntitySet(Pet))' 
to 'System.Linq.IQueryable(Pet)'. 
An explicit conversion exists (are you missing a cast?) 

Failed Attempts:

Direct casting didn’t work: (IQueryable<MyType>)

Calling collection method AsQueryable didn’t work: .AsQueryable<MyType>()

Question:

How can you cast the results of the LinqToSql query properly to IQueryable?

Cannot implicitly convert type IEnumerable<T> to IQueryable<T>