Florian Rodler, Rohit Deshpande, Maria Rosa Zapatero Osorio, Eduardo L. Martin, Michele M. Montgomery, Carlos del Burgo, Orlagh L. Creevey
Context. Radial velocity (RV) measurements from near-infrared spectra have
become a potentially powerful tool to search for planets around cool stars and
sub-stellar objects. As part of a large survey to characterize M-dwarfs using
NIRSPEC at Keck II, we obtained spectra of eight late M-dwarfs (spectral types
M5.0-M8.0) during two or more observing epochs per target. These spectra were
taken with intermediate spectral resolving powers (R \sim 20,000) in the
J-band.
Aims. We search for relative radial velocity variability in these late
M-dwarfs and test the NIRSPEC capability of detecting short period brown dwarf
and massive planetary companions around low-mass stars in the J-band (\approx
1.25 micron). Additionally, we reanalyzed the data of the M8-type star vB10
(one of our targets) presented in Zapatero Osorio et al. (2009), which were
obtained with the same instrumentation as our data.
Methods. [...]
Results. For the entire M-dwarf sample, we do not find any evidence of
relative RV variations induced by a short period brown dwarf or massive
planetary companion. The typical RV precision of the measurements is between
180 and 300 m/s, which is sufficient to detect hot Neptunes around M-dwarfs.
Also, we find that the spurious RV shift in Zapatero et al. (2009) of the star
VB10 was caused by asymmetries in the instrumental profile between different
observing epochs, which were not taken into account in their analysis.
View original:
http://arxiv.org/abs/1112.1382
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