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Abstract

In this work, the following transitions are spectroscopically investigated: Fe¹³⁺ at 530 nm, Fe⁹⁺ at 637 nm, Fe¹²⁺ at 339 nm and Fe¹⁰⁺ at 789 nm. These transitions occur in the solar corona and other stars and are therefore of astrophysical interest. Reference wavelength values are needed to determine plasma movements and temperatures in those stars, but scarce laboratory measurements are available and theoretical calculations are not sufficiently precise. In our case, those highly charged ions are produced in the laboratory using an electron beam ion trap. The wavelengths and g-factors are determined: 530.42870(8) nm, 637.6277(4) nm, 338.8930(3) nm, 789.3915(8) nm. For the Fe¹³⁺ at 530 nm, Fe⁹⁺ at 637 nm and Fe¹⁰⁺ at 789 nm transitions, the Zeeman components are well resolved. For all the measured wavelength, the uncertainty is 5-14 times smaller than for the previous best measurement.