Table 1: Selected properties of the programme Cepheid stars. Iron abundances were measured from our FEROS and UVES spectra (see Sect. 2.1). Periods, distance moduli and V-band photometry of the Galactic Cepheids are taken from Storm et al. (2004), except and from Groenewegen et al. (2004). The periods and V-band photometry for the Magellanic Cloud Cepheids were taken from Laney & Stobie (1994). The distance modulus of the barycenter of the LMC is assumed to be 18.50 (see text). The SMC is considered 0.44 mag more distant (e.g. Cioni et al. 2000). Depth and projection effects in the Magellanic Clouds were corrected for using the position angle and inclination of each galaxy as determined by van der Marel & Cioni (2001, LMC) and Caldwell & Laney (1991, SMC).

Name	log(P)	MV	[Fe/H]
Galaxy
V Cen	0.740	-3.295	+0.04
KN Cen	1.532	-6.328	+0.17
VW Cen	1.177	-4.037	-0.02
S Nor	0.989	-4.101	+0.02
T Mon	1.432	-5.372	-0.02
U Nor	1.102	-4.415	+0.07
AQ Pup	1.479	-5.513	-0.07
VZ Pup	1.365	-5.009	-0.17
RS Pup	1.617	-6.015	+0.09
RZ Vel	1.310	-5.042	-0.19
l Car	1.551	-5.821	0.00
beta Dor	0.993	-3.920	-0.14
zeta Gem	1.007	-3.897	-0.19
LMC
HV 1013	1.382	-5.037	-0.57
HV 1023	1.425	-4.994	-0.24
HV 12452	0.941	-3.899	-0.29
HV 12700	0.911	-3.627	-0.29
HV 2260	1.112	-4.067	-0.34
HV 2294	1.563	-6.050	-0.46
HV 2352	1.134	-4.656	-0.43
HV 2369	1.684	-6.215	-0.64
HV 997	1.119	-4.308	-0.14
HV 6093	0.680	-3.338	-0.49
HV 2580	1.228	-4.833	-0.18
HV 2733	0.941	-4.164	-0.26
SMC
HV 11211	1.330	-5.296	-0.67
HV 1365	1.094	-4.147	-0.67
HV 1954	1.223	-5.325	-0.67
HV 2064	1.527	-5.440	-0.55
HV 2195	1.621	-5.874	-0.61
HV 2209	1.355	-5.519	-0.56
HV 817	1.277	-5.348	-0.74
HV 823	1.504	-5.336	-0.65
HV 824	1.818	-6.669	-0.71
HV 837	1.631	-5.842	-0.69
HV 847	1.433	-5.282	-0.67
HV 865	1.523	-6.015	-0.79