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| Paper: |
Searching for Earth-mass Planets Around α Centauri: Obtaining Precise Radial Velocities from Composite Spectra |
| Volume: |
496, Living Together: Planets, Host Stars and Binaries |
| Page: |
348 |
| Authors: |
Bergmann, C.; Endl, M.; Hearnshaw, J.; Wittenmyer, R. |
| Abstract: |
For the last five years we have been undertaking an extensive
observational campaign that aims to detect terrestrial planets
in our neighboring star system α Centauri
using the Doppler method.
The most challenging problem we have encountered in reducing
the observations is the spectral cross-contamination from the
other star owing to the small angular separation between the two
components of the α Cen AB binary system. In order to
overcome this complication we have developed a modified version
of a well-established Doppler code that takes the contamination
into account by modeling the observations using two stellar
templates simultaneously.
We present some promising initial results obtained with this new data
reduction pipeline and comment on the detectability of Earth-mass
planets in the α Centauri system. After correcting for the
contamination we achieve a radial velocity precision of typically
2.5 m s–1 for a given night of observations, which
is a significant improvement of the radial velocity scatter compared
to the uncorrected velocities, thus increasing the chances of
detecting any potential terrestrial planets.
Double-lined spectroscopic binaries present a similar case of
composite spectra. Therefore, we have also applied this new Doppler
code to several double-lined spectroscopic binary systems and have
successfully recovered radial velocities for both components simultaneously. |
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