Table schema:
CREATE TABLE table_15314901_1 (condition_parameter VARCHAR, velocity_angle_η_in_i_radians VARCHAR)

Question: If the velocity angle is ln[(1 + √5)/2] ≅ 0.481, what is the condition/parameter?
SQL: SELECT condition_parameter FROM table_15314901_1 WHERE velocity_angle_η_in_i_radians = "ln[(1 + √5)/2] ≅ 0.481"