2020ApJ...899..166N

This paper presents the results of the spectrum analysis of the B-type magnetic chemically peculiar star HR 465. HR 465 shows unusual abundance patterns that vary with a period of 21.5 yr. Our observations are recorded at ph = 0.45, 0.68, and 0.85 of the spectroscopic period, where ph = 0 represents the phase of maximum flux in the photometric y-band. Synthetic spectra, computed using an LTE atmosphere model, are fit to high-resolution ultraviolet Hubble Space Telescope (ph = 0.45) spectra obtained as part of the Advanced Spectral Library Project: Hot Stars program. The ultraviolet data are supplemented by high-resolution optical spectra (ph = 0.68 and 0.85) recorded at the Nordic Optical Telescope with the SOFIN spectrograph. The optical data are used as a complement to the high line-density ultraviolet spectrum to derive accurate abundances for elements without spectral lines in the ultraviolet and to improve the abundance phase coverage for many atoms/ions. This analysis presents abundance results for more than 70 atoms/ions and confirms parts of the abundance characteristics previously reported where elements with high mass numbers show significant abundance enhancements compared with solar values while some of the lighter elements show abundance deficiencies. In addition, our measured abundances are consistent with the periodic variability for chromium and rare-earth elements. Our results are compared with earlier investigations of this peculiar object to constrain stellar abundance and diffusion.