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arXiv · 1607.00943

WISEP J060738.65+242953.4: A Nearby. Pole-On L8 Brown Dwarf with Radio Emission

John E. Gizis·Peter K. G. Williams·Adam J. Burgasser·Mattia Libralato·Domenico Nardiello·Giampaolo Piotto·Luigi R. Bedin·Edo Berger·Rishi Paudel
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Abstract

We present a simultaneous, multi-wavelength campaign targeting the nearby (7.2 pc) L8/L9 (optical/near-infrared) dwarf WISEP J060738.65+242953.4 in the mid-infrared, radio, and optical. Spitzer Space Telescope observations show no variability at the 0.2% level over 10 hours each in the 3.6 and 4.5 micron bands. Kepler K2 monitoring over 36 days in Campaign 0 rules out stable periodic signals in the optical with amplitudes great than 1.5% and periods between 1.5 hours and 2 days. Non-simultaneous Gemini optical spectroscopy detects lithium, constraining this L dwarf to be less than ~2 Gyr old, but no Balmer emission is observed. The low measured projected rotation velocity (v sin i < 6 km/s) and lack of variability are very unusual compared to other brown dwarfs, and we argue that this substellar object is likely viewed pole-on. We detect quiescent (non-bursting) radio emission with the VLA. Amongst radio detected L and T dwarfs, it has the lowest observed L_nu and the lowest v sin i. We discuss the implications of a pole-on detection for various proposed radio emission scenarios.

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John E. Gizis, Peter K. G. Williams, Adam J. Burgasser, Mattia Libralato, Domenico Nardiello, Giampaolo Piotto, Luigi R. Bedin, Edo Berger, Rishi Paudel. 2016-07-04. WISEP J060738.65+242953.4: A Nearby. Pole-On L8 Brown Dwarf with Radio Emission. https://doi.org/10.3847/0004-6256%2F152%2F5%2F123

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