1. Variability of the lowest mass objects in the AB Doradus moving group.
- Author
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Vos, Johanna M., Allers, Katelyn N., Biller, Beth A., Liu, Michael C., Dupuy, Trent J., Gallimore, Jack F., Adenuga, Iyadunni J., and Best, William M. J.
- Subjects
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STELLAR mass , *BROWN dwarf stars , *PHOTOMETRY , *RADIAL velocity of stars - Abstract
We present the detection of [3.6 μm] photometric variability in two young, L/T transition brown dwarfs, WISE J004701.06+680352.1 (W0047) and 2MASS J2244316+204343 (2M2244) using the Spitzer Space Telescope. We find a period of 16.4 ±0.2 h and a peak-to-peak amplitude of 1.07 ± 0.04 per cent forW0047, and a period of 11±2 h and amplitude of 0.8 ± 0.2 per cent for 2M2244. This period is significantly longer than that measured previously during a shorter observation. We additionally detect significant J-band variability in 2M2244 using the Wide-Field Camera on UKIRT. We determine the radial and rotational velocities of both objects using Keck NIRSPEC data. We find a radial velocity of -16.0+0.8 -0.9 km s-1 for 2M2244, and confirm it as a bona fide member of the AB Doradus moving group. We find rotational velocities of v sin i = 9.8 ± 0.3 and 14.3 -1.5+1.4 km s-1 for W0047 and 2M2244, respectively. With inclination angles of 85-9+5◦ and 76+-2014◦, W0047 and 2M2244 are viewed roughly equator-on. Their remarkably similar colours, spectra and inclinations are consistent with the possibility that viewing angle may influence atmospheric appearance. We additionally present Spitzer [4.5 μm] monitoring of the young, T5.5 object SDSS111010+011613 (SDSS1110) where we detect no variability. For periods <18 h, we place an upper limit of 1.25 per cent on the peak-to-peak variability amplitude of SDSS1110. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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