Red Supergiant

My photometry values vs. Gaia's for M36 & M38

Taking a look at the 95 datapoints, the differences between Gaia’s apparent magnitudes and mine from photometry spread out in a normal distribution as shown in figure 7. The mean difference is 0.003 magnitudes, and the 95% confidence interval ranges from -0.015 to 0.021 magnitudes. This means that not only was the mean near 0, but the confidence interval includes 0 meaning that there is no evidence to reject that my process of amateur photometry is accurate and reliable.

Data for SN 2025rbs

My experimental light curve

∆15 curve

Once I found an amateur photometry-based value for the maximum apparent magnitude of this SN Ia, I was able to determine the distance using the maximum absolute magnitude of -19.30 that Adam Riess determined. Distance is derived from the distance modulus which is: 

m - M = 5log(d)

where d is the distance in parsecs, m is the apparent magnitude, and M is the absolute magnitude. Solving for distance, the modulus becomes: 

d = 10^((m - M + 5) / 5)

which solves for the distance in parsecs. Plugging in the absolute magnitude of -19.30 and my amateur apparent magnitude of 11.43, we get: 

d = 10^((11.43 - (-19.30) + 5) / 5)

which simplifies to: 

d = 10^7.146

giving us a distance, in parsecs, of 13,995,873. Since a parsec is about 3.26 light years, the distance I calculate to the Type Ia supernova 2025rbs, and therefore the galaxy NGC 7331 is roughly 45.61 million light years (Mly).