The Appearance and Disappearance of Exocomet Gas Absorption

Figure 3

The circumstellar CaII K-line absorption spectra of HD 58647 recorded on 4 nights in March 2013. An FEB absorption event at  km s⁻¹ that is present on 03-01-2013 moves to blue wavelengths by the following night which accounts for the increase in the equivalent width of the central absorption on 03-02-2013. This “extra” absorption disappears in the spectra recorded on the following nights.