The blended ASASSN-21qj source has infrared flux near its earlier level in three 2023–2024 NEOWISE visits
Does ASASSN-21qj retain an infrared excess in the final NEOWISE visits? We extend the earlier public record through April 2024. The archive gives 60 exposures in three added visits, of which 49 pass the primary quality cuts. We measure visit medians against separate 2014–2017 seasonal baselines and 23 nearby comparison stars. The geometric mean flux ratios are 0.9958 in W1 and 1.0068 in W2. Approximate 95% intervals are 0.9710–1.0213 and 0.9760–1.0385. The error estimate combines exposure and baseline resampling with an empirical allowance from controls and earlier target scatter. All 353 rows in the earlier data table retain identical magnitudes in the final archive. Seven reductions give late flux ratios near the earlier level. The best-frame test retains only two of the three visits. The source is blended, with poor fits to a single point source. The bounds apply to mean catalog flux under the stated error model. A limit on added emission also requires stable stellar and companion flux. These data extend the known decline; they do not identify its physical cause. The package preserves raw tables, provenance, code, decisions for each row, results, and figures.
ASASSN-21qj · NEOWISE · infrared variability · debris · blended photometry · public astronomical data
References
10- doi:10.1038/s41586-023-06573-9
This paper reports the earlier event and a proposed planetary collision interpretation.
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This paper reports the infrared decline and proposes disrupted comet material as a cause. It also describes the nearby companion.
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The author correction cites the alternative interpretation.
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We use the unchanged earlier NEOWISE table to test archive agreement and identify added visits.
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We reduce final NEOWISE single-exposure data for the target and comparison stars.
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We select comparison stars from the AllWISE Source Catalog.
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This paper describes the NEOWISE Reactivation Mission and its performance.
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This paper describes the original WISE mission.
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NumPy provides the numerical calculations.
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Matplotlib provides the scientific figures.
Cited by
5 publicationsPublic catalog entries on Sciscape.
- 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
This prior archive extension is part of the known event record. Its late visits are outside our ten-visit fit.
- usesTen ASASSN-21qj infrared visits give a constant-colour p value of 0.028 under the stated error model
We reuse its raw archive tables, comparison stars, and reduction functions. We add a joint colour test and simulations.
- usesA fixed W2/W1 ratio fits added light in selected 2018–2022 ASASSN-21qj images under the stated errors
This work supplied the target and field source tables, query records, parser, and catalog quality rules through the later image study.
- usesTwo 2019 W2 difference images place the added light closer to ASASSN-21qj than to its 3.7 arcsec neighbor
We reuse its verified target and field tables, query records, original field-star list, IPAC parser, and catalog quality cuts. We add original-image position measurements.
- NEOWISE 2014–2024 shows one sudden >10% 4.6 µm brightening (TYC 9279-457-1, 2021) in 7,897 young cluster stars without IR excess; onsets are below 1.3e-4 per star-year for 2-yr exponential decays
ASASSN-21qj infrared flux in 2023–2024; this star is one of our control stars.