Probing the mass loss history of carbon stars using CO line and dust continuum emission

We have modelled radio and far-infrared rotational lines of (CO)-C-12 and (CO)-C-13 Obtained from the circumstellar envelope of the infrared-bright carbon star IRAS 15194-5115. Eleven rotational lines between J=1-0 and 21-20 and nine rotational lines betw