Bibcode
Perger, M.; García-Piquer, A.; Ribas, I.; Morales, J. C.; Affer, L.; Micela, G.; Damasso, M.; Suárez-Mascareño, A.; González-Hernández, J. I.; Rebolo, R.; Herrero, E.; Rosich, A.; Lafarga, M.; Bignamini, A.; Sozzetti, A.; Claudi, R.; Cosentino, R.; Molinari, E.; Maldonado, J.; Maggio, A.; Lanza, A. F.; Poretti, E.; Pagano, I.; Desidera, S.; Gratton, R.; Piotto, G.; Bonomo, A. S.; Martinez Fiorenzano, A. F.; Giacobbe, P.; Malavolta, L.; Nascimbeni, V.; Rainer, M.; Scandariato, G.
Bibliographical reference
Astronomy and Astrophysics, Volume 598, id.A26, 13 pp.
Advertised on:
1
2017
Journal
Citations
36
Refereed citations
33
Description
Context. The distribution of exoplanets around low-mass stars is still
not well understood. Such stars, however, present an excellent
opportunity for reaching down to the rocky and habitable planet domains.
The number of current detections used for statistical purposes remains
relatively modest and different surveys, using both photometry and
precise radial velocities, are searching for planets around M dwarfs.
Aims: Our HARPS-N red dwarf exoplanet survey is aimed at the
detection of new planets around a sample of 78 selected stars, together
with the subsequent characterization of their activity properties. Here
we investigate the survey performance and strategy. Methods: From
2700 observed spectra, we compare the radial velocity determinations of
the HARPS-N DRS pipeline and the HARPS-TERRA code, calculate the mean
activity jitter level, evaluate the planet detection expectations, and
address the general question of how to define the strategy of
spectroscopic surveys in order to be most efficient in the detection of
planets. Results: We find that the HARPS-TERRA radial velocities
show less scatter and we calculate a mean activity jitter of 2.3 m
s-1 for our sample. For a general radial velocity survey with
limited observing time, the number of observations per star is key for
the detection efficiency. In the case of an early M-type target sample,
we conclude that approximately 50 observations per star with exposure
times of 900 s and precisions of approximately 1 ms-1
maximizes the number of planet detections.
Based on observations made with the Italian Telescopio Nazionale Galileo
(TNG), operated on the island of La Palma by the Fundación
Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the
Spanish Observatorio del Roque de los Muchachos of the Instituto de
Astrofísica de Canarias (IAC).