range (Ivanova et al., in prep.). Two of our measurements coincide with these reports, notably 30 September at 11.2%/1000 ˚A and 06 February at 8.3%/1000 ˚A. While we do not report uncertainties with our maps, an uncertainty of ±1-2%/1000 ˚A should be assumed in all of our slope measurements. These uncertainties are estimated by varying the spectral window we extract slopes from, and calculating the mean difference of the different fitted regions. Furthermore, the discrepancy is also due in part to the different spectral ranges 41

(5000-7000 ˚A), which are known to cause a steeper slope at shorter wavelengths. The same reasoning cannot justify the nearly 5%/1000 ˚A discrepancy on 6 February on its own, and is likely due to the additional combination of differing apertures, use of broadband filters (including gas contamination), differing reference solar spectra, and instrument-specific spectral calibration techniques. The seasonal evolution of H2O and CO2 activity around 67P is highly dynamic and influenced by heliocentric distance and hemispheric insolation. We find evidence for hemispherical H2O anisotropy in our red-doublet [OI] maps, where H2O emission dominated the flux and distinct substructures are detected (Fig 5). We attempted to find similar anisotropic substructure in green [OI] maps (which is populated by significant CO2 and CO emission), however, none were conclusively detected, which could be due to the large SNR difference between the green and red-doublet maps. During perihelion, the comet’s southern hemisphere, which is in summer, undergoes significant erosion of a few meters, exposing volatile-rich subsurface layers (Keller et al., 2015). This process contributes to a water-dominated coma, as evidenced by our consistent G/R measurements around or less than 0.1. Ideally, this ratio would change with heliocentric distance, however, we are limited by the spectral resolution and sensitivity of MUSE, the suboptimal observing conditions, and the possible contamination of NH2. Therefore, can only report that our G/R trend is consistent with a coma dominated by H2O across our observational campaign. Finally, we find a strong morphological and evolutionary correlation between the [OI] and C2 maps, giving possible insights into the parent species and release mechanism of C2. It has been shown that the majority of water sublimation on 67P is related to the location of the subsolar point, or point of maximum insolation on the nucleus (Keller et al., 2015; L¨auter et al., 2022). We find that the approximate position angles of the [OI] structures in Figure 5 roughly correlates to the position of the subsolar point on the nucleus, as well as the C2 structures (Fig. 6). Thermophysical models, based on ROSINA measurements, depict similar evolutionary trends and sublimation zones between H2O and C2H6, especially in the southern hemisphere (L¨auter et al., 2022). These identified active spots directly sublimate H2O and C2H6, along with many other trace species (Longobardo et al., 2019). We do not find evidence for extended sources of C2 or [OI], confirming this trend, and pointing toward direct C2 photodissociation from hydrocarbon parent species like C2H6, among others.