The FERRUM project: experimentally determined metastable lifetimes and transition probabilities for forbidden [Ti ii] lines observed in eta Carinae

In the spectrum of an emission-line region ejected from the massive star Eta Carinae, called the strontium filament (SrF), forbidden lines from many elements, in particular [Sr ii] and [Ti ii], are observed. These lines are strong in this specific region and valuable for plasma diagnostics. Forbidden lines are not easily produced in laboratory light sources and the atomic parameters for these line...