Robust r-process Nucleosynthesis Beyond Lanthanides in the Common Envelop Jet Supernovae

The common envelop jet supernovae (CEJSN) r-process scenario has been proposed as an r-process nucleosynthesis site in the past decade. Jets launched by a neutron star that spirals-in inside the core of a red supergiant star in a common envelope evolution supply the proper conditions for the formation of elements heavier than iron through the rapid neutron capture process. The present work initially unveils the r-process abundance patterns that result from the density profile in the relatively long-lived jets. The results indicate that the CEJSN r-process scenario can produce the largest ratio of the third r-process peak elements to Lanthanides among current r-process scenarios, and in addition can form quite an amount of Lanthanides in a single event. The comparison of the ratio of the third peak elements to the Lanthanides with a number of observed r-enhanced metal-poor stars and with other r-process scenarios suggests that a high mass of third peak elements is anti-correlated with high fraction of Lanthanides, both in observations and theory. The CEJSN r-process scenario plays a significant role in this conclusion, since it reproduces the observational features of some particular r-enhanced metal-poor stars where other r-process scenarios encounter problems. Due to the formation of extremely heavy elements, the CEJSN also offers a credible estimation on the age of the most Actinide boosted star by cosmochronometry.