Star Types not Included in Stellar Models¶
The BEAST includes several different stellar libraries and isochrones to cover as much of the H-R diagram as possible. Stellar types that are not included in these libraries will be poorly fit, sometimes outputting nonsensical stellar parameters.
Asymptotic Giant Branch (AGB) Stars¶
The BEAST does not yet include stellar libraries that include thermally-pulsing (TP-)AGB stars. TP-AGB stars often have a large amount of circumstellar dust, causing significant extinction at shorter wavelengths. The BEAST currently identifies many of these objects as very luminous, massive stars with a unrealistic amount of interstellar extinction. Future BEAST versions will include AGB libraries.
The images below show BEAST results for a test dataset with known M type and C type AGB stars. If the AGB stars were correctly fit, they would have cooler effective temperatures (log T = 3.4 - 3.6) and lower initial masses (<8 M_sun).