Binarity constraints for Hen 3-1379 and NML Cyg

Ascertain the observational constraints on the presence of an unseen, low-mass companion in the massive evolved stars Hen 3-1379 and NML Cyg, and determine whether current data can confirm or rule out binarity in these systems.

Background

The paper discusses local analogs to the inferred circumstellar structures around SN 2024cld, including the yellow hypergiant Hen 3-1379 and the red supergiant NML Cyg, which exhibit complex, asymmetric circumstellar environments potentially shaped by binary interaction.

The authors note uncertainty about whether existing observations are sufficiently constraining to detect or exclude low-mass companions in these stars. Clarifying their binarity would help link observed circumstellar geometries in nearby massive stars to progenitor scenarios for 98S-like supernovae.

References

In both the case of Hen 3-1379 and NML Cyg, it is not clear how constraining existing observations are regarding the presence of an unseen, potentially low-mass companion -- but given the star is massive, it is not unlikely this system is also binary in nature.

— SN 2024cld: unveiling the complex mass-loss histories of evolved supergiant progenitors to core collapse supernovae  (2510.27631 - Killestein et al., 31 Oct 2025) in Section 6.3 (Discussion: Progenitor system)