Carbon star candidates from LAMOST and SDSS

Compared with the LAMOST DR11 pipeline, carbon stars by Li+ 2024, J/ApJS/271/12 and the SDSS DR18 pipeline, we identify 1403 and 1644 new candidates from LAMOST, and 661 new candidates from SDSS DR18, respectively. In our catalog, the majority of C-N, C-R, and Ba stars from LAMOST are located at low Galactic latitudes with |b|=30{deg}, while most candidates from SDSS are located at high Galactic latitudes. And the vast majority of Ba, C-H, C-R, and Unknown stars show relatively high effective temperatures.

Some carbon stars exhibit stellar activity, potentially influenced by dense interstellar materials, internal magnetic fields, and rotation effects. In the g, r, and i bands, C-N and Unknown stars from LAMOST exhibit lower S/Ns, influenced by high interstellar density at low Galactic latitudes, while Unknown stars from SDSS show higher S/Ns. Among the newly discovered carbon stars, Ba from LAMOST, Unknown from SDSS, and C-R stars have higher S/Ns than other subclasses.