Table 1: Journal of our red spectroscopic observations of WR 20a. The first and second columns provide the heliocentric Julian date (in the format HJD - 2 450 000) and the orbital phase computed using the ephemeris of Bonanos et al. (2004). Phase $\phi = 0.0$ corresponds to the "primary eclipse'' with the slightly less massive star in front. Columns 3 and 4 respectively indicate the grism used for the observation (see text) and the equivalent width of the H $\alpha$ emission line as integrated between 6499 and 6646 Å (see Sect. 4).
Date $\phi$ Grism EW(H $\alpha$ )

(Å)

3032.766 0.094 #6 33.6

3033.762 0.364 #6 28.7

3034.760 0.635 #6 31.4

3036.762 0.178 #6 31.4

3037.784 0.456 #6 35.1

3038.765 0.722 #6 31.9

3039.772 0.995 #6 42.2

3040.760 0.263 #6 31.4

3041.747 0.536 #6 40.6

3042.734 0.798 #6 31.0

3179.472 0.895 #5 26.6

**Table 1:** Journal of our red spectroscopic observations of WR 20a. The first and second columns provide the heliocentric Julian date (in the format HJD - 2 450 000) and the orbital phase computed using the ephemeris of Bonanos et al. (2004). Phase $\phi = 0.0$ corresponds to the "primary eclipse'' with the slightly less massive star in front. Columns 3 and 4 respectively indicate the grism used for the observation (see text) and the equivalent width of the H $\alpha$ emission line as integrated between 6499 and 6646 Å (see Sect. 4).
Date	$\phi$	Grism	EW(H $\alpha$ )
			(Å)
3032.766	0.094	#6	33.6
3033.762	0.364	#6	28.7
3034.760	0.635	#6	31.4
3036.762	0.178	#6	31.4
3037.784	0.456	#6	35.1
3038.765	0.722	#6	31.9
3039.772	0.995	#6	42.2
3040.760	0.263	#6	31.4
3041.747	0.536	#6	40.6
3042.734	0.798	#6	31.0
3179.472	0.895	#5	26.6

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observations
	3 The optical spectrum of WR 20a
	4 Line profile variability
	5 Fundamental parameters
	6 Discussion and future perspectives
	7 Summary and concluding remarks
	References