A Linear Relation between the Color Stretch s <sub> BV </sub> and the Rising Color Slope s<sub>0</sub>*(B-V) of Type Ia Supernovae
2023
ASTROPHYSICAL JOURNAL
DOI
10.3847/1538-4357/acc404
Using data from the Complete Nearby (redshift z (host) < 0.02) sample of Type Ia Supernovae (CNIa0.02), we find a linear relation between two parameters derived from the B - V color curves of Type Ia supernovae: the color stretch s ( BV ) and the rising color slope s(0)*(B-V) BV . The s ( BV ) parameter is known to be tightly correlated with the peak luminosity, especially for fast decliners (dim Type Ia supernovae), and the luminosity correlation with s ( BV ) is markedly better than with the classic light-curve width parameters such as ?m (15)(B). Thus, our new linear relation can be used to infer peak luminosity from s(0)* s ( BV ) (or ?m (15)(B)), the measurement of s(0)*(B-V)