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Table 4

Model parameters for the BHGs Cyg OB2 #12, ζ1 Sco, HD 190603 & BP Cru (upper panel) and Galactic B supergiant comparison (lower panel; Searle et al. 2008).

Star Spec. DM MV log (L) R Teff v β f log g M
type L R kK 10-6 M yr-1 kms-1 M

Cyg OB #12 B3-4 11.21  −9.85 6.28 246.0 13.7 3.0 400 3.0 0.04 1.70 110
ζ1 Sco B1.5 11.07  −8.50 5.93 103.0 17.2 1.55 390 2.25 0.06 1.97 36
11.50  −8.93 6.10 125.5 17.2 2.07 390 53
HD 190603 B1.5 10.98  −7.53 5.58 63.0 18.0 1.09 485 2.25 0.25 2.10 18
12.38  −8.93 6.14 120.0 18.0 2.87 485 65
BP Cru B1 12.41  −7.47 5.67 70.0 18.1 10.0 305 2.25 1.0 2.38 43

B1 5.44 36.5 22.0 2.41 12
B1.5 5.44 44.5 19.9 2.41 18
B3 5.37 60.4 16.4 2.16 19
B4 5.34 63.5 15.8 2.06 16
Star Spec vturb vesini vmacro vphot H/He N/N C/C O/O
type kms-1 kms-1 kms-1 vsound

Cyg OB #12 B3-4 12.5 38 50 0.02 10 2.7 0.21 0.55
ζ1 Sco B1.5 12.5 45 50 0.5 5 5.5 0.33 0.32
HD 190603 B1.5 15 49 55 0.5 5 5.5 0.33 0.40
BP Cru B1 10 55 0.5 3.5 4.8 2.0 0.40

Notes. R corresponds to R(τRoss = 2/3), the H/He ratio is given by number and vphot in terms of vsound. Abundances are relative to solar values from Anders & Grevesse (1989) and have uncertainties of, typically,  ~0.2 dex; if we use the values from Asplund et al. (2006) as a reference the derived ratios need to be scaled by 1.49, 1.86 and 1.86 for C, N and O respectively. The results presented here assume a distance of 1.75 kpc for Cyg OB2 #12 (DM = 11.21). Apart from the assumed distance of 1.64 kpc for ζ1 Sco (DM = 11.07, Sana et al 2006) we also provide corresponding stellar properties for the other distance estimate (1.99 kpc, DM = 11.50) assumed in previous spectroscopic studies. For HD 190603 we display the stellar properties assuming a distance of 1.57 kpc (DM = 10.98) as well as those which would result if the object had the same MV as ζ1 Sco. Finally a distance of 3.04 kpc (Kaper et al. 2006) is assumed for BP Cru.

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