Detalles de publicación
PP 06022
A multiwavelength radial velocity search for planets around the brown dwarf LP 944-20
{1}IAC
{2}University of Central Florida, Department of Physics, PO Box 162385,
Orlando, FL 32816, USA
{3}Thuringer Landessternwarte Tautenburg, 07778 Tautenburg,
Germany
{4}LAEFF-INTA, P.O. Box 50727, E-28080, Madrid, Spain
{5}Institute of Astronomy. University of Hawaii,
2680 Woodlawn Drive. Honolulu, HI 96822, USA
The nearby brown dwarf LP 944-20 has been monitored for radial
velocity variability at optical and near-infrared wavelengths using
the VLT/UVES and the Keck/NIRSPEC spectrographs, respectively.
The UVES radial velocity data obtained over 14 nights spanning
a baseline of 841 days shows significant variability with an amplitude
of 3.5 km\,s$^{-1}$. The periodogram analysis of the UVES data indicates
a possible period between 2.5 hours and 3.7 hours, which is likely due
to the rotation of the brown dwarf. However, the NIRSPEC data obtained
over 6 nights shows an rms dispersion of only 0.36 km\,s$^{-1}$ and
do not follow the periodic trend. These
results indicate that the variability seen with UVES is
likely to be due to rotationally modulated inhomogeneous
surface features. We suggest that future planet
searches around very low-mass stars and
brown dwarfs using radial velocities will be better
conducted in the near-infrared than in the optical.
velocity variability at optical and near-infrared wavelengths using
the VLT/UVES and the Keck/NIRSPEC spectrographs, respectively.
The UVES radial velocity data obtained over 14 nights spanning
a baseline of 841 days shows significant variability with an amplitude
of 3.5 km\,s$^{-1}$. The periodogram analysis of the UVES data indicates
a possible period between 2.5 hours and 3.7 hours, which is likely due
to the rotation of the brown dwarf. However, the NIRSPEC data obtained
over 6 nights shows an rms dispersion of only 0.36 km\,s$^{-1}$ and
do not follow the periodic trend. These
results indicate that the variability seen with UVES is
likely to be due to rotationally modulated inhomogeneous
surface features. We suggest that future planet
searches around very low-mass stars and
brown dwarfs using radial velocities will be better
conducted in the near-infrared than in the optical.