Neutron star-companion interaction in core collapse supernovae. Population synthesis based on detailed binary evolution models

Introduction to the show: ident: Astrophysics Radio. Generated commentary on the latest astrophysics papers.

Vera: I'm Vera, and with me are Jocelyn and Subrahmanyan, guest researcher.

Jocelyn: Today's paper: "Neutron star-companion interaction in core collapse supernovae. Population synthesis based on detailed binary evolution models".

Vera: Neutron star-companion interaction in core collapse supernovae investigates how a newly formed neutron star interacts with an inflated companion star following a supernova explosion,

Jocelyn: First, who's behind it and why it matters.

Paper summary: Vera: To summarize, this paper, "Neutron star-companion interaction in core collapse supernovae. Population synthesis based on detailed binary evolution models," investigates how a newly formed neutron star interacts with its companion star following a core-collapse supernova explosion to cause periodic light curve modulations.

Jocelyn: The central thesis is that periodic CCI is expected to occur in more than half of the binary systems that produce hydrogen-poor core collapse supernovae and are not disrupted, while the rate in systems producing hydrogen-rich supernovae is small.

Subrahmanyan: Essentially, they are using detailed binary evolution models to predict these outcomes based on the initial conditions and subsequent physical processes following the explosion.

Vera: The paper sets up this by looking at how a supernova ejecta hits a companion, causing an initial ejecta-companion interaction, which inflates the companion star. This is followed by the compact-object-companion interaction where the newly formed neutron star interacts with that inflated envelope.

Jocelyn: And they then focus on predicting what these interactions look like physically by characterizing orbital periods and eccentricities, noting that post-supernova orbital periods usually peak around twenty–fifty days.

Subrahmanyan: The paper is significant because it moves beyond just identifying a single event and attempts to derive the occurrence rate of these modulations from detailed population synthesis across various binary scenarios.

Vera: They use a state-of-the-art grid of detailed binary stellar evolution models, based on the population synthesis code SN-ORACLE (E26), which includes natal kicks sampled from distributions like DM25, K18, and V25.

Jocelyn: The methodology involves modeling the companion's response to ECI using analytic formulae where the key parameter is the fraction of kinetic energy intercepted by the companion, given by Eheat = p · Ekin,ej · Ω˜eff.

Subrahmanyan: Furthermore, they impose a condition that for these interactions to occur immediately after explosion, requiring that the post-explosion periastron distance satisfy R2 < rperi ≤ Rmax.

Vera: The paper then provides key findings on occurrence rates based on the type of supernova: H-poor supernovae are predominantly expected to exhibit periodic CCI, with fifteen point six percent of all H-poor supernovae exhibiting this periodicity in the reference model.

Jocelyn: And they also found that hydrogen-rich supernovae show a small occurrence rate for periodic CCI, reinforcing that the environment matters significantly for these interactions.

Subrahmanyan: This statistical separation based on supernova type suggests a deep connection between the progenitor's history and the resulting physical interaction frequency.

Conclusion: Vera: So, looking at this paper, "Neutron star-companion interaction in core collapse supernovae. Population synthesis based on detailed binary evolution models," it really boils down to predicting which types of systems are most likely to show these periodic interactions after a core-collapse event.

Jocelyn: The authors of the paper are using complex population synthesis techniques to map out the occurrence rates across different supernova subtypes, showing that hydrogen-poor supernovae are the prime candidates for exhibiting this periodic CCI.

Subrahmanyan: From a theoretical perspective, this work provides an important statistical prediction about how these interactions manifest in the broader population of core-collapse events, tying binary evolution directly to observational statistics.

Vera: It gives us a clearer picture of what kinds of observable signatures we should prioritize when looking at future data for periodic light curve modulations in supernova observations.

Jocelyn: And it emphasizes that these predictions are based on the detailed modeling of binary dynamics, offering a roadmap for future observational surveys.

Subrahmanyan: The implications are that we can use this framework to search for these specific physical effects in the sky more systematically than just looking at individual events in isolation.

Vera: It’s a solid piece of work that connects the detailed physics of stellar evolution to the statistical likelihood of seeing these phenomena.

Jocelyn: And it really highlights how important it is to keep developing those high-cadence and deeper time-domain surveys for this kind of search, as recommended by the authors.