J/A+A/608/A63 HADES VI. GJ 3942b activity with HARPS-N (Perger+, 2017)
HADES RV Programme with HARPS-N at TNG.
VI. GJ 3942b behind dominant activity signals.
Perger M., Ribas I., Damasso M., Morales J.C., Affer L.,
Suarez Mascareno A., Micela G., Maldonado J., Gonzalez Hernandez J.I.,
Rebolo R., Scandariato G., Leto G., Zanmar Sanchez R., Benatti S.,
Bignamini A., Borsa F., Carbognani A., Claudi R., Desidera S., Esposito M.,
Lafarga M., Martinez Fiorenzano A.F., Herrero E., Molinari E.,
Nascimbeni V., Pagano I., Pedani M., Poretti E., Rainer M., Rosich A.,
Sozzetti A., Toledo-Padron B.
<Astron. Astrophys. 608, A63 (2017)>
=2017A&A...608A..63P 2017A&A...608A..63P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Radial velocities ;
Spectroscopy ; Line Profiles
Keywords: planetary systems - techniques: radial velocities - stars: late-type -
stars: activity - stars: individual: GJ 3942 b -
methods: data analysis
Abstract:
Short- to mid-term magnetic phenomena on the stellar surface of M-type
stars can resemble the effects of planets in radial velocity data, and
may also hide them. We analyze 145 spectroscopic HARPS-N observations
of GJ 3942 taken over the past five years and additional photometry in
order to disentangle stellar activity effects from genuine Doppler
signals as a result of the orbital motion of the star around the
common barycenter with its planet. To achieve this, we use the common
methods of pre-whitening, and treat the correlated red noise by a
first-order moving average term and by Gaussian-process regression
following an MCMC analysis. We identify the rotational period of the
star at 16.3-days and discover a new super-Earth, GJ 3942b, with an
orbital period of 6.9-days and a minimum mass of 7.1MEarth. An
additional signal in the periodogram of the residuals is present, but
at this point we cannot claim with sufficient significance that it is
related to a second planet. If confirmed, this planet candidate would
have a minimum mass of 6.3MEarth and a period of 10.4-days, which
might indicate a 3:2 mean-motion resonance with the inner planet.
Description:
Data of 145 observations of GJ 3942 including RV values of TERRA and
DRS pipelines and their errors, the adopted instrumental drift,
signal-to-noise ratios, and the important activity indices.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------
16 09 03.14 +52 56 37.9 GJ 3942b = GJ 3942
--------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table9.dat 87 145 Data of 145 observations of GJ 3942
--------------------------------------------------------------------------------
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)
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.4 d BJD Barycentric Julian date (BJD-2456000)
11- 17 F7.3 m/s RVT ?=- Relative radial velocity from TERRA
pipeline (second fiber drifts already included)
19- 23 F5.3 m/s e_RVT ?=- Radial velocity error from TERRA
25- 34 F10.3 m/s RVY Radial velocity from DRS pipeline
36- 41 F6.3 m/s e_RVY Radial velocity error from DRS
43- 48 F6.3 m/s drift Instrumental RV drift of the observation
50- 54 F5.3 m/s e_drift Instrumental RV drift error
56- 59 F4.1 -- SNR signal-to-noise-ratio of order 46
61- 65 F5.3 -- S S index from CaII H and K lines
67- 71 F5.3 -- e_S S index error
73- 77 F5.3 10-2 Halpha Halpha index
79- 83 F5.3 10-2 e_Halpha Halpha index error
85- 87 A3 -- Notes Notes (1)
--------------------------------------------------------------------------------
Note (1): Notes as follows:
1 = instrumental drift measured with second fiber
2 = instrumental drift calculated
3 = no instrumental drift available
4 = spectra not used
--------------------------------------------------------------------------------
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
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
(End) Manuel Perger [IEEC-CSIC, Spain], Patricia Vannier [CDS] 28-Sep-2017