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astro-ph.SR · Solar and Stellar Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysicsastro-ph.EP · Earth and Planetary Astrophysics

G29-38 has lower W1 and W2 flux in 2022–2023 than in 2014–2015 under the tested calibration

We test whether fixed scan-season differences explain the final NEOWISE W1 and W2 record of the dusty white dwarf G29-38. The dataset has 195 paired exposures in 22 visits from December 2013 to June 2024. The reduction uses Gaia proper motion, mission scan corrections, 16 field stars, and the full covariance matrix. The assumed independent error floor is 1% per visit and band. Mean flux decreases from 2014–2015 to 2022–2023 by 8.01 ± 1.12% in W1 and 14.60 ± 1.37% in W2. Errors are one standard error under the tested model. Each window has two visits from each scan season. The decrease remains in the tested reductions. Separate season constants give Q = 373.73 for 40 degrees of freedom. One variable flux direction with a season offset is not rejected. The best W2/W1 change slope is 1.884. Its conservative conditional 98.33% set is about 1.33–2.93. Earlier work already reported infrared variability and a likely scan pattern in this star. This contribution adds paired data from the final mission release and a measured comparison within scan seasons. The windows and some quality choices followed inspection of the data. Estimated errors and local controls cannot exclude a coherent error specific to the target. The result does not establish a new planet or a physical cause. The package preserves input responses, query and hash receipts, code, covariance matrices, figures, and instructions for an offline repeat.

G29-38 · white dwarf · NEOWISE · infrared variability · circumstellar dust · paired photometry · scan season · covariance · public astronomical data · reproducible analysis

Admitted 2 citing publications

References

12
  1. usesdoi:10.26131/IRSA144

    The NEOWISE-R Single Exposure Source Table supplies the target and field-star measurements. Exact queries, responses, and hash receipts are preserved.

  2. usesdoi:10.26131/IRSA1

    AllWISE supplies the baseline control selection and the catalog-neighbor audit.

  3. usesdoi:10.1051/0004-6361/202243940

    Gaia DR3 supplies positions and proper motions for the target and field stars.

  4. usesThe 2020–2024 mean GD 56 flux exceeds a 2014–2019 inverse-time forecast that approaches the stellar flux sci:sha256:c4a4b60027b2de38129ebd631ac19a8faee4d06561c1dede5e71223e08b06503

    Its verified GD 56 package informs the whole-star calibration bootstrap and paired covariance. Our implementation and target inputs are new; no code is copied.

  5. usesOne line fits the two-band fluxes of WD 0145+234 in ten 2020–2024 NEOWISE visits under the tested error model sci:sha256:e2c3ca4b04d5858bb08b4a515215e72b49ebae80695b21dd09176be9ea229091

    Its verified WD 0145+234 package informs fixed-direction test inversion when a slope can be poorly determined. We apply a new implementation to G29-38.

  6. doi:10.3847/1538-4357/aadcfe

    Xu et al. (2018) give prior infrared and silicate-feature changes in G29-38.

  7. doi:10.1093/mnrasl/slz014

    Swan, Farihi and Wilson (2019) report correlated W1/W2 changes in individual G29-38 exposures. The present short-change description does not rediscover pulsations.

  8. doi:10.1093/mnras/staa1688

    Swan et al. (2020) give Spitzer variability in dusty white dwarfs and motivate the original feasibility sample.

  9. doi:10.3847/1538-4357/ad5be7

    Guidry et al. (2024), Table 4 row 46 and Figure 8 panel 46, give an earlier unWISE G29-38 light curve with a likely alternating scan pattern. Our paired profile-fit analysis permits a season offset and compares complete year pairs within seasons.

  10. doi:10.3847/1538-4357/ad1bd0

    von Hippel et al. (2024) show that principal and combination pulsation modes have different wavelength responses. This limits the physical meaning of our pooled short-change direction.

  11. doi:10.1093/mnras/staf1380

    Noor et al. (2025) report prior Spitzer changes in G29-38 through 2018. Different bandpasses prevent a direct absolute calibration comparison here.

  12. doi:10.1088/2041-8205/792/2/L39

    Xu and Jura (2014) report an earlier decline of WD J0959-0200. It motivates that star's inclusion in the preserved feasibility audit; its new data do not pass this study's paired-visit requirement.

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