WISE measurements of unresolved light near V1309 Sco increased in W1 and decreased in W2 from 2014–2016 to 2021–2024

We tested whether later unresolved infrared measurements near the 2008 stellar merger V1309 Sco were stable. We used the public NEOWISE Final Data Release. We compared six visits from March 2014 to September 2016 with six visits from August 2021 to March 2024. Each period has equal counts in the two scan seasons. The main sample has zero artifact flags and uses a nearby star reference. Its late/early ratios are 1.171 in W1 and 0.854 in W2. The band wavelengths are 3.4 and 4.6 micrometers. The color change is −0.342 mag. Descriptive 95% resampling ranges are 1.122–1.224 and 0.820–0.892. These ranges exclude unknown instrument and crowding errors. Broader quality cuts, separate scan seasons, different endpoint widths, and fixed aperture image measurements retain a W1 increase and a W2 decrease. A visit stack check gives ratios of 1.166 and 0.870 over its usable visits, which end in March 2023. WISE does not separate the remnant from a nearby star. The source has poor profile fits, and no changing object is identified. If one positive variable component is added to constant nonnegative light in each band, the opposite changes require its W1/W2 ratio to increase. This is a conditional model test, without a temperature estimate. The endpoint comparison was selected after initial data inspection. The package preserves 496 public input files, their provenance, analysis code, tables, figures, and a clean reproduction check.

V1309 Scorpii · stellar mergers · NEOWISE · infrared variability · source blending · reproducible photometry