Time profile of the measured ⁴⁴Ti activity in units of disintegrations per minute per kg of Fe + Ni for meteorites which fell between 1766 and 2001. Black dots depict measurements in meteorites. Error bars correspond to 1σ uncertainties in the ⁴⁴Ti activity. The black curve represents the trend of the ⁴⁴Ti activity as given by a χ² fit of Model 11 to the data. Dark-gray and light-gray shaded areas denote, respectively, the 1σ (68.27%) and 2σ (95.45%) confidence bands. The inset shows the time profile of the modulation potential (in MV) obtained from inverting Eq. (3) (see text for details).