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arXiv · 2609.18646

A homogeneous analysis of archival and new low-resolution spectra of YZ Cancri

Zhibin Dai·Lihuan Yu·Jiao Li·Xuefei Chen·Zhanwen Han
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Abstract

YZ Cancri is an SU UMa-type dwarf nova with sparse and heterogeneous optical spectroscopy. We present a homogeneous analysis of archival outburst-related spectra and seven new low-resolution quiescent spectra. We consistently characterize the Balmer, He I, Fe II, O I, and occasional He II and Bowen features, and assess which state-dependent differences are robustly supported. We applied a common continuum-normalization and line-measurement procedure, measuring equivalent widths, integrated line intensities, and selected profile parameters, and comparing line morphologies and intensity ratios between quiescent and outburst-related states. Because the spectra have modest and nonuniform resolving power and are not orbital-phase resolved, profile widths and centroid shifts are used only as relative diagnostics. Outburst-related spectra are dominated by broad Balmer absorption or composite profiles, whereas quiescent spectra show strong single-peaked Balmer and He I emission, recurrent Fe II λ5169, and weak O I λ7772 emission. He II λ4686 is detected in only two quiescent exposures, and the Bowen blend in one. The quiescent Balmer decrement is relatively flat, while the He I ratios show substantial exposure-to-exposure scatter. The measured Fe II ratios show no clear systematic departure from optically thin reference values, although blending limits their interpretation. These spectra establish an empirical state-dependent description of YZ Cnc and provide a reference dataset for future phase-resolved, higher-resolution spectroscopy.

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Zhibin Dai, Lihuan Yu, Jiao Li, Xuefei Chen, Zhanwen Han. 2026-09-16. A homogeneous analysis of archival and new low-resolution spectra of YZ Cancri. https://doi.org/10.1051/0004-6361%2F202661949

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