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arXiv · 1912.07692

Improved infrared photometry and a preliminary parallax measurement for the extremely cold brown dwarf CWISEP J144606.62$-$231717.8

Federico Marocco·J. Davy Kirkpatrick·Aaron M. Meisner·Dan Caselden·Peter R. M. Eisenhardt·Michael C. Cushing·Jacqueline K. Faherty·Christopher R. Gelino·Edward L. Wright
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Abstract

We present follow-up $Spitzer$ observations at 3.6$\mu$m (ch1) and 4.5$\mu$m (ch2) of CWISEP J144606.62$-$231717.8, one of the coldest known brown dwarfs in the solar neighborhood. This object was found by mining the Wide-field Infrared Survey Explorer ($WISE$) and $NEOWISE$ data via the CatWISE Preliminary Catalog by Meisner et al. (2019b), where an initial $Spitzer$ color of ch1$-$ch2 = 3.71$\pm$0.44 mag was reported, implying it could be one of the reddest, and hence coldest, known brown dwarfs. Additional $Spitzer$ data presented here allows us to revise its color to ch1$-$ch2 = 2.986$\pm$0.048 mag, which makes CWISEP J144606.62$-$231717.8 the 5th reddest brown dwarf ever observed. A preliminary trigonometric parallax measurement, based on a combination of $WISE$ and $Spitzer$ astrometry, places this object at a distance of 10.1$^{+1.7}_{-1.3}$ pc. Based on our improved $Spitzer$ color and preliminary parallax, CWISEP J144606.62$-$231717.8 has a $T_{\rm eff}$ in the 310$-$360 K range. Assuming an age of 0.5$-$13 Gyr, this corresponds to a mass between 2 and 20 $M_{\rm Jup}$.

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Federico Marocco, J. Davy Kirkpatrick, Aaron M. Meisner, Dan Caselden, Peter R. M. Eisenhardt, Michael C. Cushing, Jacqueline K. Faherty, Christopher R. Gelino, Edward L. Wright. 2019-12-16. Improved infrared photometry and a preliminary parallax measurement for the extremely cold brown dwarf CWISEP J144606.62$-$231717.8. https://doi.org/10.3847/2041-8213/ab6201

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