Elemental abundance analyses with DAO spectrograms

Abstract

Abstract. Elemental abundances analyses of the superfically normal B and A stars α Dra (A0 III), τ Her (B5 IV), γ Lyr (B9 III), and HR 7926 (B8 II-III) are performed consistent with previous studies of this series using spectrograms obtained with Reticon and CCD detectors. Comparisons of the first two analyses with those of the same stars performed earlier in this series which used mostly coadded photographic plates show the general consistency of the derived elemental abundances. A slight increase in the adopted effective temperature produces a corresponding increase in the derived abundances. In these stars the He/H ratios are found to be close to solar. Except for γ Lyr the metals show for the most part marginally subsolar abundance values. But this star has Al, Ca, Sc, and Sr abundances that are substantially underabundant as well as other underabundant values.

The puzzling Maia candidate star $\alpha$ Draconis

“…Fundamental parameters (Adelman et al 2001) and evolutionary tracks indicate a primary mass of 2.8±0.2 M (see Fig. 5).…”

The spectroscopic signature of roAp stars

“…Clearly, up to about 10 500 K abundances increase with temperature, which immediately calls for another investigation: is there a similar trend for normal stars and/or is this trend artificially caused by incorrect model atmospheres and spectrum reduction techniques? For this purpose we compiled Cr and Fe abundances for normal, superficially-normal, Am and δ Scuti-type stars with low rotational velocities (v e sin i < 50 km s −1 ) from papers by Varenne & Monier (1999, Hyades A and F stars), Hill & Landstreet (1993), Mittermayer & Weiss (2003), and from numerous papers by Adelman and co-workers: Adelman (1991, 1994, 1996, Adelman & Davis Philip (1992), Adelman et al (1997Adelman et al ( , 2000Adelman et al ( , 2001, , Adelman & Albayrak (1998), Pintado & Adelman (2003), and Kocer et al (2003).…”

Spectroscopic monitoring of 10 new northern slowly pulsating B star candidates discovered from the HIPPARCOS mission

“…After prewhitening with any of them, we find candidates for a third frequency which all differ from each other. Adelman et al (2001) report that on some of their high resolution, high signal-to-noise spectra, the metal lines are asymmetric. Line-profile variations have also been reported recently by Masuda & Hirata (2000), who obtained 30 spectra in 5 nights for He i λλ4471 and Mg ii λλ4481.…”