Jean-Louis Halbwachs, Michel Mayor, Stéphane Udry
Wide binaries are tracers of the gravity field of the Galaxy, but their study
requires some caution. A large list of common proper motion stars selected from
the AGK3 were monitored with the CORAVEL spectrovelocimeter, in order to
prepare a sample of physical binaries with very wide separations. Sixty-six
stars received special attention, since their RV seemed to be variable. These
stars were monitored over several years in order to derive the elements of
their spectroscopic orbits. In addition, 10 of them received accurate RV
measurements from the SOPHIE spectrograph of the T193 telescope at the
Observatory of Haute-Provence.
For deriving the orbital elements of double-lined spectroscopic binaries
(SB2), a new method was applied, which assumed that the RV of blended
measurements are linear combinations of the RV of the components. Thirteen SB2
orbits were thus calculated.
The orbital elements were eventually obtained for 52 spectroscopic binaries
(SB), two of them making a triple system. Forty SB received their first orbit,
and the orbital elements were improved for 10 others. In addition, 11
spectroscopic binaries were discovered with very long periods for which the
orbital parameters were not found. The median period of the 40 first orbits is
1 year, and several SB should be resolved or should receive an astrometric
orbit in the future, providing the masses of the components. In addition, it
appeared that HD 153252 has a close companion which is a candidate brown dwarf
with a minimum mass of 50 Jupiter masses.
The final selection of the wide binaries and the derivation of their
statistical properties will be presented in a second paper.
View original:
http://arxiv.org/abs/1112.1612
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