Gaia DR3 5792808347020475136: onset of a hot circumstellar dust component on a K dwarf in 2018, found in NEOWISE time-domain photometry

A K dwarf at 248 pc (Gaia DR3 5792808347020475136, TIC 402328069, 2MASS J14435201-7611457) whose mid-infrared brightness stepped up by 17 % at 3.4 µm and 40 % at 4.6 µm between 2 March and 11 August 2018, and has stayed up through the end of the NEOWISE mission (March 2024) with no fading and no optical change. The extra light is a ~1050 K component re-emitting about 1.6 % of the starlight, consistent with fine dust at ~0.035 AU; its temperature has not changed across twelve epochs. In 2010 the star had no infrared excess at all. The detection rests on 261 quality-cut NEOWISE single exposures, an independent PSF-matched reduction of 828 raw frames, difference imaging, ten same-brightness control stars in the same frames, the light curves of the three nearest neighbours including HD 128641 (32″ away, 36× brighter), centroid tests, both scan orientations, and optical photometry from SkyMapper (six bands, three epochs inside the jump window), ASAS-SN and TESS. Twenty-five tests are listed in the report; none produced an alternative to dust around this star. The star's age is not known (no archival spectrum exists; not X-ray detected by eROSITA; thin-disc kinematics). No prior mention of this object's infrared behaviour exists in SIMBAD, VSX, ADS or arXiv as of 2 November 2026. Contents: report (PDF and Markdown), per-epoch and per-exposure NEOWISE photometry, raw-frame photometry, control-star and neighbour light curves, SkyMapper and ASAS-SN photometry, catalogue records, difference-image montage, and a SkyMapper colour image of the field taken on 24 April 2018, within the onset window. Analysis assisted by AI Agents; all data from public archives (IRSA, Gaia, MAST, SkyMapper, ASAS-SN, HEASARC).