Models of the ejection velocity of dust from 289P as a function of particle radius. The SSA model (blue curve) and the Whipple model (red curve) are compared. The blue circle marks the particle radius a_d = 1 mm and the velocity v_d = 0.5 m s⁻¹ determined by the 1956 Phoenicids studies (Section 3.2). The black symbol indicates a_d = 2.3 μm and v_d < 48 m s⁻¹ limited by the FWHM of 289P in the W2 band (Section 3.1).