Notes. The number density is calculatedusing ρ_N = q ⋅ r^−p in [cm⁻³ ] with r given in [AU]. The temperature is given by T = a ⋅ r^−b in [K] with r given in [AU]. The parameter p is taken from the given literature (reference), whereas q, a, and b are calculated from boundary conditions like n_in and n(1000 AU), or r_in and r(10 K) in the given reference. ⁽¹⁾Average Class I object age.⁽²⁾Chemical age of source taken from Brinch et al. (2009); Jørgensen et al. (2004a). ⁽³⁾ The temperature is fixed, i.e., no temperature gradient is assumed (pre-stellar core). ⁽⁴⁾ Chemical age of source taken from Bizzocchi et al. (2014).

References: [1] Kristensen et al. (2012); [2] Lindberg & Jørgensen (2012); [3] Caselli et al. (2002); [4] Bizzocchi et al. (2014).