tokens: becomes more highly extinct and fainter. Fig. 4 LUCI J -band image of T Tauri from November 2016 displayed on a logarithmic scale. The dotted arc indicates the northern arm of the reflection nebulosity discussed by Stapelfeldt et al. (1998) . The yellow arrows indicate the tadpoles. The red arrows mark bow-shaped features. Extended features around an apparent cavity are enclosed within the black dotted lines. The green, orange, and red dots identify the locations of T Tauri N, T Tauri Sa, and T Tauri Sb, respectively. The inset shows the tadpoles and the cavity with a different gray-scale cut. Fig. 5 Zoom of Fig. 4 on the area southwest of T Tauri N showing the coiling structure and the reflection nebulosity features R2 and R3 (as shown in Fig. 2 of Kasper et al. 2016 ) in the vicinity of T Tauri S. The dotted line connects the inflection points of the coil. The red arrow indicates T Tauri Sa. Fig. 6 T Tauri H 2 line emission map obtained with LBT-LUCI in October 2016. Only features which cannot be explained by image processing artifacts are indicated and discussed in the text. The positions of the stars are indicated by colored dots (T Tauri N, Sa,and Sb are in green, orange, and red, respectively). Fig. 7 IRDIS J -band image of the coiling structure taken in December 2018. The white dotted line indicates the coiling structure’s position in December 2014 (see Kasper et al. 2016 ). The relative distance to the T Tauri stars can be determined from the orbital solution and radial velocity (RV) measurements. According to the best-fit T Tauri N-S orbit ( Schaefer et al. 2020 ), T Tauri S went through the line of nodes in 1936 with an RV difference to T Tauri N of about ± 6.5 km s −1 . The sign of the RV difference cannot be determined from an astrometric orbit solution. Duchêne et al. (2005) found that the heliocentric RVs of T Tauri Sa and Sb appear to be larger than the one of T Tauri N ( Hartmann et al. 1986 ) by 2–3 km s −1 . These values are compatible with the orbit prediction within the error bars if T Tauri S previously went through the ascending node. Since then, T Tauri S has been moving behind T Tauri N for about 80 yr and would now be located roughly 90 AU behind T Tauri N. However, the N-S orbit is still only loosely constrained and orbital solutions may exist for which T Tauri S is located in front of T Tauri N, as suggested by Beck et al. (2020) . Fig. 8 IRDIS J -band image of the R4 structure taken in December 2018. The white dotted line indicates R4’s position, and the “+” symbols indicate the positions of T Tauri Sa and Sb in December 2014 (see Kasper et al. 2016 ). Fig. 9 IRDIS J -band image of the R3 structure taken in December 2018. The white dotted line indicates R3’s position in December 2014 (see Kasper et al. 2016 ). Figure 1 also shows a bow shock at ~1′′.6 west of T Tauri. This bow shock is a signpost of the east–west outflow ( Böhm Solf 1994 ; Herbst et al. 1997 ) with the western part approaching (blue-shifted) at about
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