J/A+A/622/A193 Gl686 RV curves and BVR photometry (Affer+, 2019)
HADES RV programme with HARPS-N at the TNG.
IX. A super-Earth around the M dwarf Gl686.
Affer L., Damasso M., Micela G., Poretti E., Scandariato G., Maldonado J.,
Lanza A.F., Covino, E., Garrido Rubio A., Gonzalez Hernandez J. I.,
Gratton R., Leto G., Maggio A., Perger M., Sozzetti A., Suarez Mascareno A.,
Bonomo A.S., Borsa F., Claudi R., Cosentino R., Desidera S., Giacobbe P.,
Molinari E., Pedani M., Pinamonti M., Rebolo R., Ribas I., Toledo-Padron B.
<Astron. Astrophys. 622, A193 (2019)>
=2019A&A...622A.193A 2019A&A...622A.193A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, M-type ; Exoplanets ;
Spectroscopy ; Radial velocities
Keywords: techniques: radial velocities - techniques: photometric -
methods:data analysis - stars: individual: Gl686 -
instrumentation: spectrographs - planets and satellites: detection
Abstract:
The HArps-n red Dwarf Exoplanet Survey is providing a major
contribution to the widening of the current statistics of low-mass
planets, through the in-depth analysis of precise radial velocity
measurements in a narrow range of spectral sub-types.
Using the HARPS-N spectrograph we reach the precision needed to detect
small planets with a few earth masses. Our survey is mainly focused on
the M-dwarf population of the northern hemisphere.
As part of that programme, we obtained radial velocity measurements of
Gl686, an M1 dwarf at d=8.2pc.
These measurements show a dispersion much in excess of their internal
errors. The analysis of data obtained within an intensive observing
campaign, demonstrates that the excess dispersion is due to a coherent
signal, with a period of 15.53d.
Almost simultaneous photometric observations were carried out within
the APACHE and EXORAP programmes to characterize the stellar activity
and to distinguish periodic variations related to activity from
signals due to the presence of planetary companions, complemented also
with ASAS photometric data. We used a Bayesian framework to estimate
the orbital parameters and the planet minimum mass, and to properly
treat the activity noise. We took advantage of the available radial
velocity measurements for this target from other observing campaigns.
The analysis of the radial velocity composite time series from the
HIRES, HARPS and HARPS-N spectrographs, consisting of 198 measurements
taken over 20 years, enabled us to address the nature of periodic
signals and also to characterize stellar physical parameters (mass,
temperature and rotation).
We report the discovery of a super-Earth orbiting at a distance of
0.092AU from the host star Gl686. Gl686 b has a minimum mass of
7.1±0.9M_⊕ and an orbital period of 15.532±0.002d. The
analysis of the activity indexes, correlated noise through a Gaussian
process framework and photometry, provides an estimate of the stellar
rotation period at 37d, and highlights the variability of the spot
configuration during the long timespan covering 20yrs. The observed
periodicities around 2000d likely point to the existence of an
activity cycle.
Description:
In table tablea1.dat we report the observational radial velocity data
of Gl686, collected with the HARPS-N and HARPS spectrographs (from
TERRA pipeline), the uncertainties are the internal errors. The star
Gl686 has been monitored: from BJD=2453159.7 (June 3, 2004) to
BJD=2455458.5 (September 19, 2010), using the optical echelle HARPS
spectrograph on the ESO La Silla telescope (Mayor et al.,
003Msngr.114...20M), obtaining 20 spectra at high resolution (archive
public data); from BJD=2456700.7 (February 12, 2014) to BJD=2458047.3
(October 20, 2017), using the HARPS-N spectrograph on the TNG
telescope, as part of the HADES programme. Observations were gathered
without the simultaneous Th-Ar calibration, which is usually used to
correct for instrumental drifts during the night. Perger et al.,
2017A&A...598A..26P 2017A&A...598A..26P demonstrated that we can account for the lack of
inter-night instrumental drift adding quadratically a mean
instrumental drift of 1m/s to the RV uncertainties. The RVs were
measured by matching the spectra with a high S/N template obtained by
coadding the spectra of the target, as implemented in the TERRA
pipeline (Anglada-Escude & Butler, 2012ApJS..200...15A 2012ApJS..200...15A). We list the
observation dates (barycentric Julian date or BJD), the radial
velocities (RVs) from TERRA pipeline, the formal RV errors (not
including the jitter term) and the instrument used (HARPS, HARPS-N).
In table apache.dat we report the differential photometry of
Gl 686 in V-band, obtained using the APACHE array, located at the
Astronomical Observatory of the Autonomous Region of the Aosta Valley
(OAVdA, +45.7895 N, +7.478 E, 1650 m.a.s.l.).
Each telescope is a Carbon Truss f/8.4 Ritchey-Chretien equipped with
a GM2000 10-MICRON mount and a FLI Proline PL1001E-2 CCD Camera, with
a pixel scale of 1.5"/pixel and a field of view of 26'x 26'. The
observations were carried out using a Johnson-Cousins V filter
following the standard strategy used by APACHE (Sozzetti et al.,
2013EPJWC..4703006S 2013EPJWC..4703006S). The images were reduced with the standard
pipeline TEEPEE written in IDL by the APACHE team (see Giacobbe et
al., 2012MNRAS.424.3101G 2012MNRAS.424.3101G). We list the observation dates (Heliocentric
Julian date or HJD), the relative flux and uncertainty in the V-band.
In tables exorapb.dat, exorapv.dat, exorapr.dat we report
the differential photometry of Gl 686 in BVR-bands, obtained using an
80cm f/8 Ritchey-Chretien robotic telescope (APT2) located at Serra la
Nave (+14.973 E, +37.692 N, 1725 m a.s.l.) on Mt. Etna. We used
aperture photometry as implemented in the IDL routine, trying a range
of apertures to minimize the rms of the ensemble stars (6 stars). We
list the observation dates (Julian date or JD), the relative magnitude
and uncertainty in the B/V/R-bands.
Objects:
-------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------
17 37 52.8 +18 35 21 Gl 686 = BD+18 3421
-------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 48 84 Observing log, RVs and errors
apache.dat 40 1660 Apache differential photometry and errors of
Gl 686 (V-band)
exorapb.dat 33 81 Exorap differential photometry and errors of
Gl 686 (B-band)
exorapv.dat 33 65 Exorap differential photometry and errors of
Gl 686 (V-band)
exorapr.dat 33 50 Exorap differential photometry and errors of
Gl 686 (R-band)
--------------------------------------------------------------------------------
See also:
J/A+A/593/A117 : GJ 3998 RVs, S and Halpha indexes (Affer+, 2016)
J/A+A/598/A26 : HADES RV Programme with HARPS-N at TNG. II. (Perger+, 2017)
J/A+A/605/A92 : GJ 625 HARPS-N data (Suarez Mascareno+, 2017)
J/A+A/608/A63 : HADES VI. GJ 3942b activity with HARPS-N (Perger+, 2017)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d BJD Barycentric Julian date
16- 21 F6.3 m/s RVT Radial velocities with TERRA (1)
28- 32 F5.3 m/s e_RVT Error of RVs with TERRA (1)
42- 48 A7 --- Inst Spectrograph
--------------------------------------------------------------------------------
Note (1): TERRA pipeline (Anglada-Escude & Butler, 2012ApJS..200...15A 2012ApJS..200...15A).
Average radial velocity has been subtracted from all the radial velocities.
-------------------------------------------------------------------------------
Byte-by-byte Description of file: apache.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d HJD Heliocentric Julian date
20- 27 F8.6 --- RelFlux Relative flux in V Band
33- 40 F8.6 --- e_RelFlux Uncertainty in relative flux in V Band
--------------------------------------------------------------------------------
Byte-by-byte Description of file: exorapb.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 F15.7 d JDB Julian date in B band
18- 24 F7.4 --- RelmagB Relative magnitude in B band
28- 33 F6.4 --- e_RelmagB Uncertainty in relative magnitude B band
--------------------------------------------------------------------------------
Byte-by-byte Description of file: exorapv.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 F15.7 d JDV Julian date in V band
18- 24 F7.4 --- RelmagV Relative magnitude in V band
28- 33 F6.4 --- e_RelmagV Uncertainty in relative magnitude in V band
-------------------------------------------------------------------------------
Byte-by-byte Description of file: exorapr.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 F15.7 d JDR Julian date in R band
18- 24 F7.4 --- RelmagR Relative magnitude in R band
28- 33 F6.4 --- e_RelmagR Uncertainty in relative magnitude in R band
-------------------------------------------------------------------------------
Acknowledgements:
Laura Affer, laura.affer(at)inaf.it
References:
Affer et al., Paper I 2016A&A...593A.117A 2016A&A...593A.117A, Cat. J/A+A/593/A117
Perger et al., Paper II 2017A&A...598A..26P 2017A&A...598A..26P, Cat. J/A+A/598/A26
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
Suarez Mascareno et al., Paper V 2017A&A...605A..92S 2017A&A...605A..92S, Cat. J/A+A/605/A92
Perger et al., Paper VI 2017A&A...608A..63P 2017A&A...608A..63P, Cat. J/A+A/608/A63
Mascareno et al., Paper VII 2018A&A...612A..89M 2018A&A...612A..89M
Pinamonti et al., Paper VIII 2018A&A...617A.104P 2018A&A...617A.104P
(End) Patricia Vannier [CDS] 18-Jan-2019