[astro-ph.SR] We present the discovery of SMDET-1, a red, fast-moving object (μ≈1.3″/yr) identified in time-resolved unWISE coadds using a pixel-level deep learning methodology called SMDET.
Despite being relatively bright at 4.5 microns compared to many other recent WISE-based brown dwarf discoveries (m[4.5]≈14.6 mag Vega), SMDET-1 had remained overlooked due to its location in a very crowded Galactic plane field (b≈2.25∘) and contamination from brighter background objects. SMDET-1 is also serendipitously detected at 4.5 microns in late-2012 Spitzer Deep GLIMPSE survey imaging.
SMDET-1 is undetected in UKIDSS and Palomar/WIRC near-infrared imaging, with the strongest constraint on its temperature (Teff < 391 K) arising from its Deep GLIMPSE color limit of m[3.6]−m[4.5]>2.81 mag, which also implies a very nearby photometric distance < 7.4 pc. The Spitzer color bound corresponds to a Y dwarf phototype.
SMDET-1 illustrates the importance of continued searches for nearby brown dwarfs within archival datasets like WISE and Spitzer, as well as the potential of pixel-level deep learning to discover astronomical moving objects that challenge traditional data analysis approaches.
The Backyard Worlds: Planet 9 Collaboration: Aaron M. Meisner, Dan Caselden, Federico Marocco, J. Davy Kirkpatrick, Jonathan Gagné, Adam C. Schneider, Samuel A. Beiler, Sergio B. Fajardo-Acosta, Jacqueline K. Faherty, Stanimir A. Metchev, Sam Barber, Marc J. Kuchner, Thomas P. Bickle, Zafar Rustamkulov
Comments: accepted for publication in AJ
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2608.00046 [astro-ph.SR] (or arXiv:2608.00046v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2608.00046
Focus to learn more
Submission history
From: Aaron Meisner
[v1] Fri, 24 Jul 2026 18:01:15 UTC (715 KB)
https://arxiv.org/abs/2608.00046
Astrobiology
