sciscape Publications
← All publications
astro-ph.SR · Solar and Stellar Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysicsastro-ph.EP · Earth and Planetary Astrophysics

SPHEREx QR2 does not establish a red excess at TYC 9279-457-1 in 2025–2026 when ten field stars set the calibration

We tested whether public SPHEREx Quick Release 2 images show a red infrared excess at TYC 9279-457-1 after its reported 2021 brightening. We measured the target and ten nearby field stars in 316 image files. The final comparison uses Gaia positions, old 2MASS fluxes, pre-event NEOWISE fluxes, and wavelength bins present in every star. The target is 3.80% above the control mean in the nominal 4.2–5.0 micrometer window and 3.47% above it in the 3.0–3.8 micrometer window. The longer/shorter window color offset is 0.33%, with a conditional 95% calibration range from −4.23% to 5.10%. The target color lies inside the measured control range. All tested color ranges include zero when we change the fit, aperture, reference fluxes, dates, or control set. The ranges require independent normal star residuals with the same distribution. They are not unconditional bounds on dust light. Apertures have larger scatter. The windows were observed on different dates, the pixel fits have large residuals, and a faint optical neighbor remains unresolved. If the old W2 decay stays unchanged, it predicts a 2.8–3.5% remnant during these observations. The new data can contain such a remnant, but this comparison does not establish that it persists or that it has ended. The package has saved pixels, source URLs, code, figures, results, and reproduction steps. A checked download restores Gaia catalog columns under their separate license.

TYC 9279-457-1 · SPHEREx · NEOWISE · infrared excess · debris disks · photometric calibration · forced photometry · control stars · reproducible astronomy

Admitted 1 citing publication

References

7
  1. usesNEOWISE 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 sci:sha256:8c92cb19323fd77db200c046907e2aef3762bbeb054811e00b553962dba86297

    This work discovered the 2021 event. We reuse its corrected target visits and reproduce its old W2 decay fit before comparison to later SPHEREx data.

  2. usesSPHEREx QR2 detects the 0.75–5 µm excess of 47 of 78 clean MO26 white dwarfs with G < 17, and of all 22 with a WISE-predicted S ≥ 10; background sources cause the 2 excesses in 56 clean controls sci:sha256:af7c2da87b4e4e4ceb8480a7b8b3ff3e107a9be0c32cbd4d3b425c516590b6b1

    We reuse its MIT spxphot.py code without change to extract QR2 pixels and supplied PSFs. New code refits the saved pixels and compares the target to ten field stars.

  3. usesdoi:10.26131/IRSA144

    Independent NEOWISE single-exposure requests set the pre-event W1 and W2 reference values for all eleven stars.

  4. usesdoi:10.26131/IRSA1

    AllWISE and its associated 2MASS fluxes define the control selection and the old near-infrared reference values.

  5. usesdoi:10.1051/0004-6361/202243940

    Gaia DR3 positions and proper motions set the final fit positions. Gaia optical data also define an exploratory luminosity subset. Catalog columns are restored from ESA under their separate license.

  6. usesdoi:10.48550/arXiv.2511.15823

    This paper describes the public SPHEREx image pipeline and supplied PSF products used for the QR2 measurement.

  7. usesdoi:10.1088/0004-637X/735/2/112

    WISE flux zero points convert the old W1 and W2 magnitudes into reference fluxes.

Cited by

1 publication

Public catalog entries on Sciscape.