J/A+A/598/A26 HADES RV Programme with HARPS-N at TNG. II. (Perger+, 2017)
The HADES RV Programme with HARPS-N at TNG.
II. Data treatment and simulations.
Perger M., Garcia-Piquer A., Ribas I., Morales J.C., Affer L., Micela G.,
Damasso M., Suarez-Mascareno A., Gonzalez-Hernandez 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.
<Astron. Astrophys. 598, A26 (2017)>
=2017A&A...598A..26P 2017A&A...598A..26P (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Spectroscopy ; Stars, M-type; Stars, nearby ;
Radial velocities
Keywords: methods: statistical - techniques: radial velocities - surveys -
stars: low-mass - planetary systems
Abstract:
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. 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. 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. We find that
the HARPS-TERRA radial velocities show less scatter and we calculate a
mean activity jitter of 2.3m/s 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 900s and precisions of
approximately 1m/s maximizes the number of planet detections.
Description:
Intrinsic and observational characteristics of the 78 target stars of
our sample sorted by number of observations (Nobs).We show the
absolute RVs and their rms and the mean uncertainties dRV of every
object for TERRA (T) and YABI (Y) pipelines. V magnitudes are from
SIMBAD. Their masses are the average values of targets with the same
spectral type.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 88 78 Characteristics of our target stars
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See also:
J/A+A/593/A117 : Paper I. GJ 3998 RVs, S and Halpha indexes (Affer+, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Target name
24- 26 I3 --- Nobs Number of observations
28- 31 A4 --- SpType Spectral type
33- 36 F4.2 Msun M Stellar mass
38- 41 F4.2 Msun e_M ? Stellar mass uncertainty
43- 47 F5.2 mag Vmag Visual magnitude
50- 54 F5.2 km/s RV ? Absolute radial velocity (YABI)
56- 60 F5.2 m/s RVTrms ? rms of TERRA radial velocities
62- 65 F4.2 m/s e_RVT Mean TERRA radial velocity uncertainty
67- 71 F5.2 m/s RVYrms ? rms of YABI radial velocities
73- 76 F4.2 m/s e_RVY Mean YABI radial velocity uncertainty
78- 82 F5.1 --- S/N ? Signal-to-noise ratio of observation
84- 88 A5 --- Flag Flag (1)
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Note (1): Notes as follows:
1 = Stars form the subsample for Sec 3.4.
2 = Large rms differences between TERRA and DRS/YABI mentioned in Fig. 3
3 = TERRA RV uncertainties estimated
4 = DRS/YABI RV uncertainties estimated
5 = spectral types from SIMBAD
6 = companion by Howard et al. (2014ApJ...794...51H 2014ApJ...794...51H)
7 = companion by Affer et al. (2016A&A...593A.117A 2016A&A...593A.117A)
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Acknowledgements:
Manuel Perger, perger(at)ice.cat
References:
Affer et al., Paper I 2016A&A...593A.117A 2016A&A...593A.117A, Cat. J/A+A/593/A117
Maldonado et al., Paper III 2017A&A...598A..27M 2017A&A...598A..27M
Scandariato et al., Paper IV 2017A&A...598A..28S 2017A&A...598A..28S
(End) Manuel Perger [CSIC-IEEC, Spain], Patricia Vannier [CDS] 07-Nov-2016