ner_tags: O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O B-Model O O O O O O O O O O O O O O O O O O O B-Telescope O O B-Telescope O O O B-Instrument O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation O O O O O O O O O O O O O O O O
tokens: which indicates the importance of non-equilibrium chemistry in the inner wind. Moreover, as the initial HCN abundance of R Dor and IK Tau lie within a factor of 2 of each other, quite similar physical and chemical conditions are likely present in their inner winds independent of mass-loss rate. The factor of 2 difference might be due to the lower mass-loss rate of R Dor or different pulsation characteristics. Fig. 8 Black: integrated line strengths of HCN modelled using a Gaussian abundance profile characterised by = with respect to H and cm. Overplotted are the integrated line strengths measured with APEX (red circles), SEST (blue circles), and HIFI (purple circles). The error bars for the resolved molecular lines correspond to an absolute error of 20%. Fig. 9 Range in abundance profiles found for HCN throughout the CSE. The molecular transitions probe the region marked between dashed vertical lines. 6. Conclusions We have constrained the radial abundance profile of SiO and HCN in the stellar wind of the low mass-loss M-type AGB star R Dor using a non-LTE extended atmosphere model that accounts for the interaction between gas and dust. Our analysis used the integrated line intensity and line profile shapes of a set of lines obtained with both ground- and space-based instruments. For SiO, we used 42 molecular transitions, of which 16 are spectrally resolved. The molecular data are sensitive to the region between approximately 5 and 100 . The initial abundance of SiO lies between and with respect to H. The abundance profile is constant up to , after which it follows a Gaussian profile with an e-folding radius between cm. The decline in SiO abundance near 60 might be due to condensation onto dust grains or photodissociation. We are unable to unambiguously determine the mechanism at work. For HCN, we used five resolved molecular transitions. The molecular data are sensitive to the region between approximately 7 and 40 . The initial abundance of HCN lies between and with respect to H. The abundance profile is a Gaussian profile centred on the star with an e-folding radius between cm. The initial abundances found are higher than those reported in previous studies (with the exception of the study by Khouri 2014 , for SiO). This might be due to our inclusion of higher- molecular lines. Compared to results for IK Tau, a high mass-loss rate M-type AGB star, the onset of photodissociation occurs closer to the star for both SiO and HCN. This can be explained by their difference in mass-loss rate. The R Dor initial abundance of SiO is also higher than those found for IK Tau. This might be due to different pulsation characteristics of the central stars and/or a difference in dust condensation physics. It is not connected to a differing sensitivity to non-equilibrium chemistry in the inner wind, as this molecule is unaffected by such processes ( Cherchneff 2006 ). For both stars, we find roughly similar HCN abundances, though both are five orders of