Keywords: Molecular clouds (1072); Collapsing clouds (267); Star forming regions (1565); Star formation (1569); Astrochemistry (75); Early stellar evolution (434)

1. INTRODUCTION

2. OBSERVATIONS  
2.1. ALMASOP

3. RESULTS  
3.1. 1.3 mm and 1.1 mm continuum – A compact nucleus in the filamentary cloud  
3.2. Dense gas tracers  
3.3. Outflow tracers  
3.4. \(N_{2}D^{+}\) emission with high spectral resolution

4. ANALYSIS  
4.2. \(N_{2}D^{+}\) Column Density  
4.3. \(N_{2}D^{+}\) abundance

5. DISCUSSION  
5.1. Physical properties of the filament  
5.2. Radial density profile of the nucleus

6. DISCUSSION  
6.1. Chemical stratification in G208-N2  
6.3. Evolutionary stage of the nucleus  
6.4. Shock compression  
6.5. End-dominated collapse in the filamentary structure

7. SUMMARY