We present a comprehensive mid-infrared spectroscopic survey of 124 Herbig Ae/Be stars using newly processed Spitzer/IRS spectra from the newly released CASSISjuice database.
![Distribution of the 11.0/11.2 PAH band ratio versus stellar effective temperature for our HAeBe sample. Reference stars (SR 21A, PDS 144N, HD 97300) shows different ionization regimes. The shaded regions approximate PDR-like ranges from JWST data, whereas very low ratios occur at 5000–6000 K suggestive of neutral PAHs in low mass disk. MWC 137, which is showing very low ionization is likely an evolved B[e] star rather than an HAeBe star. -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/06/Polycyclic-Aromatic-Hydrocarbons-In-The.png?resize=1200%2C720&ssl=1)
We present a comprehensive mid-infrared spectroscopic survey of 124 Herbig Ae/Be stars using newly processed Spitzer/IRS spectra from the newly released CASSISjuice database.