SF of the full light curve (blue triangles) and t ≤ 08 : 13 UTC (red circles). The dashed blue line is the fit to the SF of the full light curve (slope = 0.81). The dashed black line is the fit to the first six data points (slope = 1.22), and the dotted black line indicates the tentative break at 549 s. The dashed red line is the fit to the SF of the t ≤ 08 : 13 UTC light curve (slope = 0.80).