Table 1
Physical properties of Cas A.
| Parameter | Symbol (units) | Calculated/ | Observed/ | References |
| adopted | estimated | |||
| value | value | |||
|
|
||||
| Progenitor mass | (M⊙) | 19a | 15–25 | 1, 2 |
| Distance | (kpc) | 3.4a | 3.4 | 3 |
| Age (2004) | (yr) | 333a | 333 | 4 based on 5 |
| Explosion energy | E (1051 erg) | 2.2b | 2.0 | 6 |
| Ejecta mass | Mej (M⊙) | 2.0b | 2.2 | 7, 8 |
| Forward shock radius | Rb (pc) | 2.50c* | 2.32–2.72 | 9, 10, 11 |
| Reverse shock radius | Rr (pc) | 1.71c* | 1.52–2.01 | 9, 10, 11, 12 |
| Forward shock velocity | vb (km s-1) | 5226c* | 4000–6000 | 13 |
| Reverse shock velocity | vr (km s-1) | 1586c* | 1000–2000 | 6, 12 |
| Circumstellar density (pre-shock) | n0 (cm-3) | 2.07b | 1.99 | 8 |
| Density contrast clumps/smooth ejecta | χ | 100a | ≈100 | 14 |
| Ejecta clumps density (pre-shock) | ncloud (cm-3) | 100a | 100–300 | 14, 15 |
| Smooth ejecta density (pre-shock) | nsmooth (cm-3) | 1.0c | 0.1–10 | 12 |
| Ejecta clumps diameter | 2Rcloud (cm) | 1.5 × 1016a | (1−5) × 1016 | 16 |
Notes.
Reference. [1] Young et al. (2006), [2] Vink et al. (1996), [3] Reed et al. (1995), [4] Hwang & Laming (2012), [5] Thorstensen et al. (2001), [6] Laming & Hwang (2003), [7] Willingale et al. (2002), [8] Willingale et al. (2003), [9] Hwang & Laming (2012), [10] Helder & Vink (2008), [11] Gotthelf et al. (2001), [12] Morse et al. (2004), [13] DeLaney & Rudnick (2003), [14] Sutherland & Dopita (1995), [15] Docenko & Sunyaev (2010), [16] Fesen et al. (2011).
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