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arXiv · 2111.08182

Discovery of CWISE J052306.42-015355.4, an Extreme T Subdwarf Candidate

Hunter Brooks·J. Davy Kirkpatrick·Dan Caselden·Adam C. Schneider·Aaron M. Meisner·Jacqueline K. Faherty·S. L. Casewell·Marc J. Kuchner·The Backyard Worlds·:·Planet 9 Collaboration
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Abstract

We present the discovery of CWISE J052306.42$-$015355.4, which was found as a faint, significant proper motion object (0.52 $\pm$ 0.08 arcsec yr$^{-1}$) using machine learning tools on the unWISE re-processing on time series images from the Wide-field Infrared Survey Explorer. Using the CatWISE2020 W1 and W2 magnitudes along with a $J-$band detection from the VISTA Hemisphere Survey, the location of CWISE J052306.42$-$015355.4 on the W1$-$W2 vs. $J-$W2 diagram best matches that of other known, or suspected, extreme T subdwarfs. As there is currently very little knowledge concerning extreme T subdwarfs we estimate a rough distance of $\le$ 68 pc, which results in a tangential velocity of $\le$ 167 km s$^{-1}$, both of which are tentative. A measured parallax is greatly needed to test these values. We also estimate a metallicity of $-1.5 <$ [M/H] $< -0.5$ using theoretical predictions.

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Hunter Brooks, J. Davy Kirkpatrick, Dan Caselden, Adam C. Schneider, Aaron M. Meisner, Jacqueline K. Faherty, S. L. Casewell, Marc J. Kuchner, The Backyard Worlds, :, Planet 9 Collaboration. 2021-11-16. Discovery of CWISE J052306.42-015355.4, an Extreme T Subdwarf Candidate. https://doi.org/10.3847/1538-3881%2Fac3a0a

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