A spectroscopic study of weak metallic emission lines in a B3 V star ι Herculis

Abstract

Abstract We present a list of weak emission lines (WELs) observed in a sharp-lined B3 V star ι Her (HD 160762) using high-resolution (R = 65000) and high-S/N (∼1300) spectral data. The list covers a spectral region between 4900 Å and 10000 Å. We registered 207 WELs in this star and identified 190 lines including ten ions (nine elements). Emission lines of C ii, N i, Cr ii, Mn ii, and Ni ii have been identified among normal B-type stars for the first time. Seventeen emission lines remain unidentified. We compared our list with the published list of WELs for 3 Cen A (Wahlgren & Hubrig, 2004, A&A, 418, 1073) and found that the numbers of detected emission lines reflect differences in abundance between these two stars. We detected 13 C i emission lines in ι Her (normal in C), while only one C i emission line was found in 3 Cen A (deficient in C). Many emission lines of P ii and Cu ii have been detected in 3 Cen A (over-abundant in both P and Cu), while no emission line of these ions has been found in ι Her. Many emission lines of Fe ii are visible in the shorter-wavelength side of 6000 Å in ι Her, while these emission lines are missing in 3 Cen A. Close inspections of spectral data of 3 Cen A reveal that the apparently missing Fe ii lines appear as absorption lines in this star. Because these two stars have nearly the same atmospheric parameters (Teff and log g), a physical interpretation that is independent of these two parameters is needed to account for this observation.