KIC 9832227: Using Vulcan Data to Negate The 2022 Red Nova Merger Prediction

Abstract: KIC 9832227 is a contact binary whose 11 hr orbital period is rapidly changing. Based on the apparent exponential decay of its period, the two stars were predicted to merge in early 2022 resulting in a rare red nova outburst. Fortunately KIC 832227 was observed in 2003 as part of the NASA Ames pre-Kepler Vulcan Project to search for transiting exoplanets. We find that the Vulcan timing measurement does not agree with the previous exponential decay model. This led us to re-evaluate the other early epoch non-Kepler data sets, the Northern Sky Variability Survey (NSVS) and Wide Angle Search for Planets (WASP) survey. We find that the WASP times are in good agreement with the previous prediction, but the NSVS eclipse time differs by nearly an hour. The very large disagreement of the Vulcan and NSVS eclipse times with an exponentially decaying model forces us to reject the merger hypothesis. Although period variations are common in contact binaries, the physical cause of the period changes in KIC 9832227 remains unexplained; a third star scenario is unlikely. This study shows the data collected by the Vulcan photometer to be extremely valuable for extending the baseline for measurements of variable stars in the Kepler field.

• The paper challenges the exponential decay model by using Vulcan data to refute the 2022 red nova merger prediction for KIC 9832227.
• The analysis integrates multi-epoch datasets to construct an Observed minus Computed diagram that exposes significant orbital period discrepancies.
• The study suggests that common period variability in contact binaries may be driven by magnetic cycles or mass transfer rather than a third stellar companion.

An Analysis of "KIC 9832227: Using Vulcan Data to Negate The 2022 Red Nova Merger Prediction"

The paper "KIC 9832227: Using Vulcan Data to Negate The 2022 Red Nova Merger Prediction" by Socia et al. addresses an intriguing problem in the study of contact binaries and red novae, particularly focusing on the observed orbital period changes in KIC 9832227—a binary system previously predicted to experience a merger in 2022. The analysis presented utilizes archival data from multiple sources, offering significant insight into the limitations of the exponential decay model formerly proposed to predict the merger.

This paper refocuses the attention from a merger hypothesis to a broader examination of period variability common to contact binaries, enriched by the analysis therein. Specifically, observations made with the Vulcan photometer revealed discrepancies that undermine the previously hypothesized exponential decay model prediction for KIC 9832227. Notably, Vulcan's data departs significantly from the earlier established timeline, emphasizing the eclipsing timings' inconsistency with the merger hypothesis.

Equipped with data from different epochs, including NSVS and WASP surveys, the paper presents a detailed Observed minus Computed (O-C) diagram challenging the previous assumption of inevitable binary coalescence. The authors present compelling evidence against the exponentially decaying prediction from Molnar et al., revisiting the eclipse timings and re-evaluating the ephemeris of the system.

The implications of this study extend notably into the domain of contact binary studies, particularly concerning the causal theories of period variations. The paper identifies that period wanderings akin to those found in KIC 9832227 are prevalent in similar stellar systems, suggesting mechanisms such as magnetic cycles or mass transfer as potential underlying causes. However, the paper dismisses the possibility of a third stellar companion due to the lack of spectral evidence and poor model fit.

This research signifies the importance of historical datasets, in this case, the Vulcan project, in extending our understanding of variability within binary systems. Moreover, the meticulous analysis and cross-verification with available data are critical for accurately interpreting period dynamics in contact binaries.

Looking forward, the study sparks interest in continuing analyses of contact binaries to explore and confirm alternative explanations for period discrepancies, particularly those unaccounted for by exponential decay models. The paper highlights a keen necessity for precise long-term monitoring and extensive datasets in resolving period variations and potential instabilities within these systems.

In conclusion, the paper provides a stringent review of previously accepted hypotheses regarding the KIC 9832227 system. It obligates the scientific community to reconsider predictive models used in the study of contact binaries and red novae, emphasizing the need for precise observational data and comprehensive model testing in resolving stellar behavior complexities. This work underscores how rigorous data re-evaluation can prompt significant shifts in our understanding of stellar phenomena.