English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We surveyed 20 AGB stars of different chemical types using the APEXtelescope, and combined this with an IRAM 30 m and APEX survey of CS and SiSemission towards over 30 S-type stars. For those stars with detections, weperformed radiative transfer modelling to determine abundances and abundancedistributions. We detect CS towards all the surveyed carbon stars, some S-typestars, and the highest mass-loss rate oxygen-rich stars ($> 5\times 10^{-6}$Msol yr$^{-1}$). SiS is detected towards the highest mass-loss rate sources ofall chemical types ($> 8\times 10^{-7}$ Msol yr$^{-1}$). We find CS peakfractional abundances ranging from ~ $ 4\times 10^{-7}$ to ~ $2\times 10^{-5}$for the carbon stars, from ~ $ 3\times 10^{-8}$ to ~ $1\times 10^{-7}$ for theoxygen-rich stars and from ~ $ 1\times 10^{-7}$ to ~ $8\times 10^{-6}$ for theS-type stars. We find SiS peak fractional abundances ranging from ~ $ 9\times10^{-6}$ to ~ $ 2\times 10^{-5}$ for the carbon stars, from ~ $ 5\times10^{-7}$ to ~ $ 2\times 10^{-6}$ for the oxygen-rich stars, and from ~ $2\times 10^{-7}$ to ~ $ 2\times 10^{-6}$ for the S-type stars. We derivedSi$^{32}$S/Si$^{34}$S = 11.4 for AI Vol, the only star for which we had areliable isotopologue detection. Overall, we find that wind density plays animportant role in determining the chemical composition of AGB CSEs. It is seenthat for oxygen-rich AGB stars both CS and SiS are detected only in the highestdensity circumstellar envelopes and their abundances are generally lower thanfor carbon-rich AGB stars by around an order of magnitude. For carbon-rich andS-type stars SiS was also only detected in the highest density circumstellarenvelopes, while CS was detected consistently in all surveyed carbon stars andsporadically among the S-type stars.

Sulphur-bearing molecules in AGB stars II: Abundances and distributions of CS and SiS