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

A grey thermal model with constant temperature fits ten selected 2018–2022 ASASSN-21qj visits better than a model with constant area under fixed baseline light and the stated errors

We compare two grey thermal models for ten selected 2018–2022 ASASSN-21qj infrared visits. We use published image fluxes, their full shared-baseline covariance, and band-integrated Planck spectra. The baseline light is fixed. One model has one area and ten temperatures. The other has one temperature and ten areas. Their residual sums are Q = 14.406 and 8.986, each with nine reference degrees of freedom. Gaussian simulations with 5000 refits per model give residual-test p values of 0.104 and 0.436. Both pass that test. An added exploratory comparison favors the constant-temperature model: 47 of 5000 draws from the fitted constant-area model give a Q difference at least as large as the observed 5.420. The corrected tail fraction is 0.0096. This comparison is conditional on the fitted mean and covariance. The constant-temperature fit gives 983 K. Its final projected area is 0.112 of the mean early area, with a conditional 95% profile interval of 0.057–0.166. Aperture and field-error choices change the constant-area reference p value from 0.00033 to 0.85. Constant band-gain shifts up to 10% have little effect on its primary Q. We preserve the code, input tables, covariance, calibration files, hashes, simulations, and figures. This is a new physical fit test of existing measurements. It does not establish contraction, exclude cooling in general, or identify the cause of the event.

ASASSN-21qj · NEOWISE · thermal emission · projected area · shared baseline covariance · model comparison · reproducible research

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References

17
  1. usesA fixed W2/W1 ratio fits added light in selected 2018–2022 ASASSN-21qj images under the stated errors sci:sha256:54380b8d9fe6d1bdf8d64b8c4136cf92fe1147c4a9e93b42f81a12b0176a5e54

    We use its public image coadd measurements, accepted pairs, full primary covariance, and MIT estimate code. We add a comparison of two physical thermal models and conditional area ratios.

  2. usesTen ASASSN-21qj infrared visits give a constant-colour p value of 0.028 under the stated error model sci:sha256:378e7fb1a635c429fc297c6e64f6b2a76c2e622b6e3dfac17e45603bf7272413

    This prior color study supplies preserved official WISE band responses and motivates careful use of baseline covariance. Its temperature discussion is prior work.

  3. The blended ASASSN-21qj source has infrared flux near its earlier level in three 2023–2024 NEOWISE visits sci:sha256:2111d70dce9993c8de3f8feda9b58c62a884ff88a94a03826971209354727b18

    This prior archive extension is part of the known event record. Its late visits are outside our ten-visit fit.

  4. Two 2019 W2 difference images place the added light closer to ASASSN-21qj than to its 3.7 arcsec neighbor sci:sha256:643d6cad3305a84eb0bffeb9bfce2abf789f5f1d8251894f0413510d79dad9ab

    This prior source-location study describes the known close neighbor. The blended aperture remains a limit on physical interpretation.

  5. doi:10.1038/s41586-023-06573-9

    This primary event study proposes a planetary collision and already discusses nearly fixed temperature and contraction. We test specified thermal descriptions of later published measurements.

  6. doi:10.1038/s41586-023-06874-z

    This author correction links the independent event study.

  7. doi:10.3847/1538-4357/ace629

    This primary event study proposes a comet event and reports dust temperatures. The physical temperature interpretations are prior work.

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    This paper describes the WISE band responses and calibration used for spectral integration.

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  10. usesdoi:10.26131/IRSA147

    The source image study derives our input measurements from these public NEOWISE single-exposure images. The original cutouts remain in that signed source.

  11. usesdoi:10.26131/IRSA144

    The original source study uses the NEOWISE source data for exposure selection.

  12. usesdoi:10.26131/IRSA1

    The original image calibration uses AllWISE reference magnitudes.

  13. usesdoi:10.5270/esa-qa4lep3

    The original field selection uses Gaia DR3 positions and motions.

  14. usesdoi:10.1038/s41586-020-2649-2

    NumPy supplies numerical arrays and linear algebra.

  15. usesdoi:10.1038/s41592-019-0686-2

    SciPy supplies optimization, interpolation, and probability functions.

  16. usesdoi:10.1051/0004-6361/201322068

    Astropy reads the CALSPEC FITS spectrum.

  17. usesdoi:10.1109/MCSE.2007.55

    Matplotlib makes the figures.

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