Recent work suggests that Type Ia supernovae ( SNe ) are composed of two distinct populations : prompt and delayed .
By explicitly incorporating properties of host galaxies , it may be possible to target and eliminate systematic differences between these two putative populations .
However , any resulting post -calibration shift in luminosity between the components will cause a redshift-dependent systematic shift in the Hubble diagram .
Utilizing an existing sample of 192 SNe Ia , we find that the average luminosity difference between prompt and delayed SNe is constrained to be ( 4.5 \pm 8.9 ) \% .
If the absolute difference between the two populations is 0.025 mag , and this is ignored when fitting for cosmological parameters , then the dark energy equation of state ( EOS ) determined from a sample of 2300 SNe Ia is biased at \sim 1 \sigma .
By incorporating the possibility of a two-population systematic , this bias can be eliminated .
However , assuming no prior on the strength of the two-population effect , the uncertainty in the best-fit EOS is increased by a factor of 2.5 , when compared to the equivalent sample with no underlying two-population systematic .
To avoid introducing a bias in the EOS parameters , or significantly degrading the measurement accuracy , it is necessary to control the post-calibration luminosity difference between prompt and delayed SN populations to better than 0.025 mag .