Properties of Heavy Cosmic Nuclei Phosphorus, Chlorine, Argon, Potassium, and Calcium: Results from the Alpha Magnetic Spectrometer

We report the unique properties of cosmic phosphorus (P), chlorine (Cl), argon (Ar), potassium (K), and calcium (Ca) fluxes in the GV to TV rigidity range collected by the Alpha Magnetic Spectrometer (AMS) on the International Space Station. With a total of one million events collected over 13.5 years, we observed that the rigidity dependencies of the five fluxes are well described by the sums of a primary cosmic ray component and a secondary cosmic ray component. The abundance ratios of all five elements to Si at the source are accurately determined independent of cosmic ray propagation. The source abundance of Ar and Ca (even- <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mi>Z</a:mi> </a:mrow> </a:math> elements) is larger than P, Cl, and K (odd- <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>Z</c:mi> </c:math> elements). The secondary components of the P and the Cl fluxes are each <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mo>∼</e:mo> <e:mn>1</e:mn> <e:mo>/</e:mo> <e:mn>3</e:mn> </e:math> of the F flux, and the secondary components of the Ar, K, and Ca fluxes are each <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mo>∼</g:mo> <g:mn>1</g:mn> <g:mo>/</g:mo> <g:mn>2</g:mn> </g:math> of the F flux. The twenty elements measured by AMS, from He to Ca and Fe, can be categorized into four classes, two primary and two secondary, based on their rigidity dependence.