Stellar masks and bisector’s shape for M-type stars observed in the GAPS Programme with HARPS-N at TNG. (arXiv:2002.06844v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+Rainer_M/0/1/0/all/0/1">Monica Rainer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borsa_F/0/1/0/all/0/1">Francesco Borsa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Affer_L/0/1/0/all/0/1">Laura Affer</a>

The HARPS/HARPS-N Data Reduction Software (DRS) relies on the
cross-correlation between the observed spectra and a suitable stellar mask to
compute a cross-correlation function (CCF) to be used both for the radial
velocity (RV) computation and as an indicator of stellar lines asymmetry,
induced for example by the stellar activity. Unfortunately the M2 mask
currently used by the HARPS/HARPS-N DRS for M-type stars results in heavily
distorted CCFs. We created several new stellar masks in order to decrease the
errors in the RVs and to improve the reliability of the activity indicators as
the bisector’s span. We obtained very good results with a stellar mask created
from the theoretical line list provided by the VALD3 database for an early
M-type star (T$_{mathrm{eff}}$=3500~K and $log{g}=4.5$). The CCF’s shape and
relative activity indicators improved and the RV time-series allowed us to
recover known exoplanets with periods and amplitudes compatible with the
results obtained with HARPS-TERRA.

The HARPS/HARPS-N Data Reduction Software (DRS) relies on the
cross-correlation between the observed spectra and a suitable stellar mask to
compute a cross-correlation function (CCF) to be used both for the radial
velocity (RV) computation and as an indicator of stellar lines asymmetry,
induced for example by the stellar activity. Unfortunately the M2 mask
currently used by the HARPS/HARPS-N DRS for M-type stars results in heavily
distorted CCFs. We created several new stellar masks in order to decrease the
errors in the RVs and to improve the reliability of the activity indicators as
the bisector’s span. We obtained very good results with a stellar mask created
from the theoretical line list provided by the VALD3 database for an early
M-type star (T$_{mathrm{eff}}$=3500~K and $log{g}=4.5$). The CCF’s shape and
relative activity indicators improved and the RV time-series allowed us to
recover known exoplanets with periods and amplitudes compatible with the
results obtained with HARPS-TERRA.

http://arxiv.org/icons/sfx.gif