K_s-band photometry of the Extreme T Subdwarf CWISE J221706.28-145437.6

2025/07/02 by Zhang, Jerry Jun-Yan, Lodieu, Nicolas, Martín, Eduardo L. · 1 citation
#Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)

paper · doi:10.48550/arxiv.2507.02022

Abstract

We present deep K_s-band imaging of the extreme T subdwarf CWISE J221706.28-145437.6. Using the new photometry, we construct its spectral energy distribution and find this object exhibits exceptionally strong collision-induced absorption in the H and K bands. The comparison with the nearest benchmark extreme T subdwarf WISEA J181006.18-101000.5 suggests the object would be cooler and more metal-poor than the benchmark.

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