Figure 1:
The RCW 114 nebula as recorded by the Southern H Sky Survey Atlas (Guastad et al. 2001) showing the positions of the target stars (1) HD 156385, (2) HD 156575, (3) HD 157042, (4) HD 157243, (5) HD 157698, (6) 157832 and (7) HD 158042.
Figure 2:
Interstellar NaI D1 D2 absorption line profiles for the seven targets observed towards the RCW 114 nebula. Solid thick lines represent the best-fit model to the observed data points, which are shown by the lighter lines. Actual model absorption components (unconvolved) are shown by the dotted lines. The absorption profiles are presented by increasing distance of the target.
Figure 3:
Interstellar NaI D1 D2 equivalent widths plotted as a function of
istance to the 7 observed stars. Notice the large increase in absorption values
for the two most distant stars.
Figure 4:
spectra of the SiII 1304 absorption line recorded towards HD 157042 (d = 221 pc), HD 157832 (d = 780 pc), HD 156575 (d = 1100 pc) and HD 156385 (d = 1550 pc). Note the marked increase in absorption complexity for the two most distant stars.