Rego Fernández, ManuelGonzález Riestra, R.Fernández Figueroa, María José2023-06-212023-06-2119830004-6361https://hdl.handle.net/20.500.14352/64989© European Southern Observatory (ESO). © EDP Sciencies.The λ 1640 feature has been observed in a sample of late type stars of different luminosity classes. The intensity was measured from IUE low dispersion spectra, and it has been compared with the observed X-ray fluxes, finding a relationship between both quantities for "solar type" stars. The X-ray fluxes derived from this relationship for a reduced sample of stars are consistent with the observed ones in the case of "solar type" stars. "Non solar type" stars exhibit discrepancies that could be explained assuming that the λ 1640 feature is formed by contributers other than He II, which supply an important fraction of this emission in "solar type" stars. The obtained empirical relationship has been used to derive the X-ray flux for some stars that have not been observed in the X-ray range.engThe relationship between soft X-rays and the 1640 Å feature fluxes in late-type starsjournal articlehttp://adsabs.harvard.edu/abs/1983A%26A...119..227Rhttp://www.aanda.orgopen access52Emission linesX-raysLate type starsAstrofísicaAstronomía (Física)