Lie-algebraic characterization of tangentially degenerate orbits of s-representations

In this paper we study tangential degeneracy of the orbits of s-representations in the sphere. We show that the orbit of an s  -representation is tangentially degenerate if and only if it is through a long root, or a short root of restricted root system of type G2G2. Moreover these orbits provide many new examples of tangentially degenerate submanifolds which satisfy the Ferus equality.