SIMBAD references

Result. of precision measurements of the net longitudinal component of magnetic field strength (B_e) performed for Procyon (α CMi, F5 IV-V) and three solar-type stars–β Com (G0 V), ζ Her (F9 IV), β Aql (G8 IV)–are reported. All stars observed are weak solarlike activity analogs. We outline an improved observational technique (Stokesmeter plus CCD detector) and data reduction process that permits determination of the mean longitudinal field strength, B_e, with an accuracy within the range 1-5 G. The average value of B_e=-1.34±1.0 G was estimated for Procyon using 10 spectral lines in the region 6285-6350 Å. A substantial magnetic field value was detected on only one occasion for ζ Her: B_e=-10.1±3.1 G.