2004A&A...420..673N

A spectrum synthesis analysis for photospheric lines in the magnetic B star HR 5049 is presented, based on a high quality spectrogram obtained with the EMMI spectrograph attached to the NTT at ESO. It is found that light elements such as He, C and O are under-abundant. One of the most notable features is the deficiency of He by more than -2.0dex. Co and Cl are over-abundant by +3.5dex and +1.9dex, respectively. Other iron peak elements are over-abundant ranging from +0.47dex (TiII) to +1.94dex (CrI). For rare earth elements, the lines of once-ionized species are generally weak, while the third spectra (especially those of Pr and Nd) are very prominent. Although rare earth elements show significant over-abundances ranging from +3.0dex to as large as +4.0dex, Ba has the solar abundance. The Nd-Pr abundance difference, which shows an apparent decreasing trend with increasing effective temperature among CP stars, is found to be unusually small in HR 5049.