Abundance of radioactive technetium in Przybylski's star revisited

TL;DR

This study searched for radioactive technetium in Przybylski's star's spectrum, finding no clear evidence of its presence and setting an upper limit on its abundance, challenging previous claims of its existence.

Contribution

The paper provides a detailed spectral analysis that questions prior evidence of technetium in Przybylski's star and establishes a new upper limit for its abundance.

Findings

No detectable technetium lines in the star’s spectrum

Set an upper abundance limit of logε(Tc/H) = 2.5

Doubts about previous claims of technetium presence

Abstract

We have searched for lines of the radioactive element technetium (Tc) in the spectrum of Przybylski's star (HD101065). The nuclei of this chemical element are formed in the slow process of capturing thermalized neutrons. The possible lines of Tc~I are heavily blended. We have synthesized the profile of one resonance line at 4297.06 \AA~, which is also a part of the complex blend, and we arrived at a decision that it is not visible in the spectrum (as was first noted by Ryabchikova), casting doubt on the existence of technetium in the atmosphere of the Przybylski's star. Therefore, based on our calculated combined profile, which has been adjusted to the observed blend profile at ~4297.2 A (that may possibly contain the resonance technetium line 4297.06 A), we reduce the maximum technetium abundance to $\log\epsilon$(Tc/H) = 2.5. This value can be considered only as an upper limit of the technetium abundance in the Przybylski's star.