The properties of a large sample of OH/IR stars, S stars and C-rich AGB stars

Abstract

We collected infrared and radio data on 110 OH/IR stars, 65 S stars and 184 C-rich stars from the literature. We analyzed their spectral energy distributions, bolometric magnitudes, infrared colors and mass-loss rates. Our study confirms that OH/IR stars and C-rich stars reach similarly high mass-loss rates at similar luminosities, supporting the idea that mass-loss rates are determined by internal stellar activities such as pulsation rather than the properties of their envelopes. The mass-loss rates of OH/IR stars and C-rich stars are strongly correlated with the color indices K-[A], K-[C], K-[D] and K-[E], and the two populations can be described with one formula. Our study also reveals that only those stars with color indices K-[A]<4 or K-[C]<5 have SEDs that peak in the near-infrared waveband.