KPF cross-correlation functions (CCFs) for HD 3167 and four comparison stars with similar atmospheric parameters and independently measured projected rotation velocities. (Left) Normalized CCFs and the KPF instrumental profile. (Right) Differences between each star’s full width and the full width of the narrowest profile (KIC 7970740), evaluated at each normalized CCF level. HD 3167 has a narrower profile than the stars with ﹩v{\rm{\sin }}i\approx 1.4﹩ km s⁻¹ and broader than the star with ﹩v{\rm{\sin }}i\approx 0.9﹩ km s⁻¹, suggesting its projected rotation velocity is between those values.