Table 3.
Input parameters used in the Meudon PDR code.
| Parameter | Value | Unit | Note |
|---|---|---|---|
| Free parameters |
|||
| Pth NGC 7023 | 108 | K cm−3 | Best fit |
| Pth Orion Bar | 2.8 × 108 | K cm−3 | Best fit |
Fixed parameters |
|||
| G0 NGC 7023 | 2600 | Habing | (1) |
| G0 Orion Bar | 2 × 104 | Habing | (2), (3) |
|
10 | mag | |
| Flux of cosmic-rays | 5 × 10−17 | s−1 per H2 | |
| Dust extinction | HD 38087 | (4) | |
| RV | 5.62 | (5) | |
| NH/E(B − V) | 1.05 × 1022 | cm−2 mag−1 | See text |
| Mass grain/Mass gas | 0.01 | ||
| Grain size distribution | ∝ a−3.5 | (6) | |
| Min radius of grains | 3 × 10−7 | cm | |
| Max radius of grains | 3 × 10−5 | cm | |
Elementary abundances |
|||
| He | 0.1 | ||
| C | 1.32 × 10−4 | (7) | |
| O | 3.19 × 10−4 | (8) | |
| S | 1.86 × 10−5 | (7) | |
| N | 7.50 × 10−5 | (9) | |
| D/H | 1.5 × 10−5 | (10) | |
| 12C/13C | 50 | (11) | |
References.
(1) For the NGC 7023 PDR model, we adopt a beamed stellar radiation field as described in the text. If converted in a Habing scaling factor, this corresponds to G0= 2600, (2) Tielens & Hollenbach (1985), (3) Marconi et al. (1998), (4) Cardelli et al. (1989), (5) Witt et al. (2006), (6) Mathis et al. (1977), (7) Savage & Sembach (1996), (8) Meyer et al. (1998), (9) Meyer et al. (1997), (10) Oliveira & Hébrard (2006), (11) intermediate value from observations in Orion (Demyk et al. 2007; Ossenkopf et al. 2013; Haykal et al. 2014).
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.