P. Petit, V. Van Grootel, S. Bagnulo, S. Charpinet, G. A. Wade, E. M. Green
We report on high-resolution spectropolarimetric observations of the hot
subdwarf stars HD 76431 and Feige 66, using the ESPaDOnS echelle
spectropolarimeter at CFHT. We compute cross-correlation Stokes I and V line
profiles to enhance the signal-to-noise ratio. We then average all available
cross-correlation profiles of each star to further decrease the noise level.
Although both targets were previously reported to host kilo-gauss magnetic
fields, we do not derive any evidence of large-scale photospheric fields from
our sets of observations, in spite of tight error bars on the longitudinal
field of the order of 60 gauss for HD 76431 and 200 gauss for Feige 66. A new
analysis of FORS1 observations of HD 76431, which provided the basis for the
original claim of field detection, confirms the absence of any detectable
Zeeman signature, with an error bar of about 100 gauss on the longitudinal
magnetic field.
View original:
http://arxiv.org/abs/1110.5227
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