Results of the SLED analysis with HC₃N lines toward P1 (left) and P2 (right). The blue and red points indicate the observed values. The 10% errors due to the typical uncertainty of the chopper-wheel method are taken into consideration. The black curves indicate the best-fitting result with the parameters shown in each panel: ﹩{n}_{{{\rm{H}}}_{2}}=1.85\times {10}^{4}﹩ cm⁻³, T _kin = 10 K (fixed), and N(HC₃N)=2.6 × 10¹³ cm⁻² for P1, and ﹩{n}_{{{\rm{H}}}_{2}}=5.1\times {10}^{4}﹩ cm⁻³, T _kin = 14.5 K, and N(HC₃N) = 9.4 × 10¹² cm⁻² for P2.