High-resolution spectroscopy of the hot Am star HR 3383

Abstract

We present the spectrum analysis of the hot Am star HR 3383 (A1 Vm). Hubble Space Telescope STIS and Nordic Optical Telescope SOFIN data are modelled with synthetic spectra, and abundances are investigated for 78 elements. Most light elements up through oxygen show deficiencies, compared to solar abundances, followed by the general trend of increasing abundance enhancement with atomic number that levels off at a 30-fold enhancement at the lanthanide-group and heavier elements. The derived element distribution is generally consistent with what is observed in other hot Am stars. Abundances for HR 3383 are also similar to what is seen for the cooler HgMn stars, with the exception of the platinum-group elements which generally show dramatic enhancements in the HgMn stars. Current theory and calculations are able to predict most observed abundances and abundance trends through the iron-group. The large number of derived element abundances in this study provides a constraint for theoretical calculations attempting to explain the heavy element abundances in chemically peculiar stars. This paper includes a comprehensive description of spectral lines useful for an abundance analysis of late B and A type stars, and comments are provided on the atomic data. New data for hyperfine structure components for three lines in Lu iii and a single line in Lu ii are presented, based on laboratory spectra. In addition to the stellar spectrum, lines from the interstellar medium are noted for several of the strongest Fe ii ultraviolet transitions.

Experimental and Theoretical Radiative Parameters of Highly Excited Odd-parity Levels in Ir ii

“…Iridium (Z = 77), as a heavy element predominantly formed by the r-process, is observed in its singly ionized form in many stars, e.g., the CP star χ Lupi (Ivarsson et al 2004), the MP halo star HD 160617 (Roederer et al 2012), the A1 Vm star Sirius (Cowley et al 2016), and the hot Am star HR 3383 (Wahlgren et al 2021) etc. Ivarsson et al (2004) used the timeresolved laser-induced fluorescence (TR-LIF) technique to measure the radiative lifetimes for nine odd-parity levels of Ir II, and combined with BFs determined by Fourier transform spectroscopic measurement, obtained the oscillator strengths and transition probabilities of 23 transitions of Ir II. Based on these data, they determined the abundance of iridium in the CP star χ Lupi.…”