Serkowski parameters λ_max and K for Galactic stars. The data are from Whittet et al. (1992, circles) and Voshchinnikov et al. (2013, squares). Filled symbols indicate objects with E_{B − V}> 0.8. The ellipses trace the 1- to 5-sigma confidence levels for the full Whittet et al. sample (for a bi-variate Gaussian distribution). For comparison, the parameters derived for SN 1986G and 2006X are plotted (large filled circles). The long-dashed line traces the Whittet et al. relation (the dashed-dotted lines indicate the ±1-sigma levels). The contours in the lower left corner of the plot indicate the 10- and 20-sigma confidence levels for SN 2008fp and 2014J. The upper left insert plots the E_{B − V} distribution of the Whittet et al. (1992) sample of 105 stars. The vertical line marks the median value of E_{B − V}, while the arrows indicate the values of the four SN (see Table 1).