Line shape terms improve predictions for alternate pixels near 7794 and 7808 Å in 53 later Proxima Centauri spectra

We test a local line shape model in four reported variable regions of Proxima Centauri. We use exact cutouts from 118 public ESO ESPRESSO spectra from 2019 to 2022. A template uses only 65 spectra from 2019. The baseline fits an offset and template scale in each narrow window. Adding the first and second template derivatives reduces squared prediction errors for alternate native pixels in 53 later spectra by 42.6% near 7794.26 Å and 33.3% near 7808.19 Å. The main window half-width is 0.13 Å. The improvement stays positive at tested half-widths of 0.10 and 0.18 Å. Near 7809.10 Å, the later prediction error increases by 16.5%. Nearby comparison windows also show line shape changes. Relations between apparent local shift and Earth velocity repeat only in part across the two periods. These results give a compact description of the selected variable profiles. They do not establish an atmospheric, stellar, or instrumental cause. The analysis choices are exploratory. Neighboring source pixels are correlated, and reduction versions differ between periods. The package preserves exact source arrays and headers, source hashes, model data, code, all tested variants, figures, and reproduction instructions.

Proxima Centauri · ESPRESSO · spectral variability · line profiles · template derivatives · public astronomical data · reproducible spectroscopy