Systematic Detection of Biogenic Elements in Ca-rich Transient Spectra: Evidence for a 20-Year Observational Bias

This dataset contains the complete analysis revealing that approximately 50% of Ca-rich transient spectra contain clear signatures of biogenic elements (Na, K, P) that have been systematically overlooked in astronomical literature for over 20 years. Furthermore, wavelength coverage analysis demonstrates that only 20.8% of available spectra cover the ranges necessary for sulfur (921-924 nm) and magnesium (515-520 nm) detection, revealing a systematic instrumental bias. When proper wavelength coverage exists, S and Mg detection rates increase by 4x and 3.3x respectively. This discovery has profound implications for astrobiology and the search for biosignatures in astronomical phenomena. Dataset includes: (1) Complete biogenic element analysis of 42 spectra from 20 Ca-rich transients, (2) Wavelength coverage analysis revealing instrumental bias, (3) Gold standard analysis of spectra with complete wavelength coverage, (4) All analysis code and visualizations, (5) Publication-ready figures and reports. This work extends our initial discovery (DOI: 10.5281/zenodo.15517217) with expanded analysis revealing the wavelength coverage bias that has hidden potential biosignatures for decades.