Chemical composition of the magnetic B star HR 5049 ^*,**

¹ Rakutou High School, Anshu, Yamashina-ku, Kyoto 607-8017, Japan
² Astronomical Institute, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582-8582, Japan
³ Osaka Science Museum, Nakanoshima, Kita-ku, Osaka 530-0005, Japan
⁴ National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588, Japan
⁵ European Southern Observatory, Casilla 19001, Santiago 19, Chile

Corresponding author: M. Nishimura, mnisimura@kcat.zaq.ne.jp

Received: 10 November 2003
Accepted: 23 February 2004

Abstract

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 -2.0 dex. Co and Cl are over-abundant by +3.5 dex and +1.9 dex, respectively. Other iron peak elements are over-abundant ranging from +0.47 dex () to +1.94 dex (). 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 +3.0 dex to as large as +4.0 dex, 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.