¹²C/¹³C isotopic abundance ratios from HC₅N. The ratios are based on the integrated intensity of the transitions of HC₅N and its ¹³C isotopologues. The ratios derived from the J = 7−6, J = 8−7, and J = 9−8 transitions are denoted with filled squares, pentagrams, and circles, respectively. The dashed line denotes the unweighted average ¹²C/¹³C value.