Activity and telluric contamination in HARPS observations of Alpha Centauri B. (arXiv:1902.10711v1 [astro-ph.SR])

Activity and telluric contamination in HARPS observations of Alpha Centauri B. (arXiv:1902.10711v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lisogorskyi_M/0/1/0/all/0/1">Maksym Lisogorskyi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jones_H/0/1/0/all/0/1">Hugh Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feng_F/0/1/0/all/0/1">Fabo Feng</a>

The Alpha Centauri system is the primary target for planet search as it is
the closest star system composed of a solar twin Alpha Centauri A, a K-dwarf
Alpha Centauri B and an M-dwarf Proxima Centauri, which has a confirmed planet
in the temperate zone. Alpha Centauri A & B were monitored intensively with the
HARPS spectrograph for over 10 years, providing high-precision radial velocity
measurements. In this work we study the available data to better understand the
stellar activity and other contaminating signals. We highlight the importance
of telluric contamination and its impact on the radial velocity measurements.
Our suggested procedures lead to discarding about 5% of HARPS data, providing a
dataset with an RMS improved by a factor of 2. We compile and quantify the
behaviour of 345 spectral lines with a wide range of line shapes and
sensitivity to activity.

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