Ground-Based Spectroscopic Detection of Iron-Bearing Material in the Dust Tail of BD+05 4868 Ab

We present ground-based spectroscopic and photometric observations of the rapidly disintegrating short-period rocky exoplanet BD+05 4868 Ab. Using low-resolution spectroscopy (R ≈ 600) with the PlaneWave CDK17 and ALPY 600 spectrograph, we detect a transit-correlated absorption feature near 7770 Å that appears only during transit, when the dust tail is most optically thick, and is absent in out-of-transit spectra. We interpret this feature as evidence for iron-bearing material (iron oxides, iron-rich silicates, or mantle-derived iron) in the planet’s escaping dust tail. Supporting multi-site photometric observations show asymmetric transit signatures consistent with an extended, structured dust tail. These results provide initial spectroscopic evidence for iron-bearing components in disintegrating planetary dust and demonstrate the feasibility of ground-based characterization of escaping interior material in systems like BD+05 4868 Ab.