On the possible presence of promethium in the spectra of HD 101065 (Przybylski's star) and HD 965

Abstract

Abstract. Traditional and statistical line-identification methods indicate the presence of Pm I and II, Tc I, and perhaps Tc II in the spectrum of the roAp star HD 101065. These methods also lead to the presence of Pm II and probably also Pm I in a related cool Ap star, HD 965. The spectroscopic evidence is strong enough that we would declare promethium to be present without hesitation, if any of its isotopes were stable. The longest-lived promethium isotope has a half-life of only 17.7 years. The presence of this element would mean that unrecognized processes -perhaps flare activities -are taking place in the atmospheres of these stars. The significance of such processes for galactic chemical evolution cannot be ruled out. We discuss the possibility that the highly improbable wavelength coincidences are due to chance, or due to contamination of the laboratory sources.

Investigation of intravalence, core–valence and core–core electron correlation effects in polonium atomic structure calculations

“…As support to further experimental or theoretical studies of nuclear properties in polonium, it is essential to know the atomic structure of this element with the highest possible accuracy. In astrophysics, recent observations have suggested the presence of short-lived radioactive elements, such as Tc (Z¼43), Pm (Z¼ 61) and 84 rZr99 elements at the surface of the chemically peculiar roAp star HD 101065, also known as Przybylski's star [7][8][9][10]. In particular, Gopka et al [8] presented the results on new identifications of the lines of all radioactive elements with atomic numbers from Z¼84 to Z¼99, except for Z¼85 (At) and Z¼87 (Fr).…”

On the radioactive shells in peculiar main sequence stars: the phenomenon of Przybylski's star.

“…A discussion on the abundance of Pm and Tc in PS and HR465, started from Aller & Cowley (1970), consists of several dozens papers and summarized by Cowley et al (2004). We continue such investigations, and this paper presents the first results on the new identification of the lines of radioactive elements in PS's spectrum.…”

“…As a comment to this Table we have to note that we confirmed previous identifications of the technetium and promethium lines made by . A small part of the lines, identified by Cowley et al (2004) appears to be lanthanides lines, but the main result is valid -Tc and Pm exist in the atmosphere of PS. We estimated the abundance of Tc in PS -it appears to be near 3.5-4 in the scale log N (H) = 12.…”

“…Shavrina et al (2003) proposed that these reactions can be responsible for the anomalous ratio of lithium isotopes in the atmosphere of PS. Cowley et al (2004) pointed that spallation reactions can produce Tc and Pm in PS.…”

“…The most outstanding feature of this star is its anomalously high atmospheric abundance of the rare elements like lanthanides. Later, Cowley (2003) and Cowley et al (2004) identified the lines of radioactive technetium and promethium in spectrum of this star. It should be noted that the presence of the thorium and uranium lines was also reported for this star.…”