J/A+A/695/A62 GJ 3998 RVs, SMW and Halpha indexes (Stefanov+, 2025)
HADES RV Programme with HARPS-N at TNG. XVI.
A super-Earth in the habitable zone of the GJ 3998 multi-planet system.
Stefanov A.K., Suarez Mascareno A., Gonzalez Hernandez J.I., Nari N.,
Rebolo R., Affer L., Micela G., Ribas I., Sozzetti A., Perger M.,
Pinamonti M., Damasso M., Maldonado J., Gonzalez Alvarez E., Scandariato G.
<Astron. Astrophys. 695, A62 (2025)>
=2025A&A...695A..62S 2025A&A...695A..62S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Spectroscopy ; Optical
Keywords: techniques: radial velocities - planets and satellites: detection -
stars: activity - stars: individual: GJ 3998
Abstract:
The low masses of M dwarfs create attractive opportunities for
exoplanet radial-velocity (RV) detections. These stars, however,
exhibit strong stellar activity that may attenuate or mimic planetary
signals. We present a velocimetric analysis on one such M dwarf, GJ
3998 (d=18.2pc), with two published short-period super-Earths:
GJ 3998 b and GJ 3998 c. We use additional data from the HARPS-N
spectrograph to confirm these two planets and to look for more. We
carry out joint modelling of: (i) RV planetary signals, (ii) stellar
rotation in RV and activity indicators through Gaussian processes,
(iii) long-term trends in RV and activity indicators. We constrain the
rotational period of GJ 3998 to Prot=30.2±0.3d and discover
long-term sinusoidal imprints in RV and FWHM of period
Pcyc=316+14-8d. We confirm GJ 3998 b and GJ 3998 c, and detect a
third planet: GJ 3998 d, whose signal had been previously attributed
to stellar activity. GJ 3998 d has an orbital period of 41.78±0.05d,
a minimum mass of 6.07+1.00-0.96M⊕ and a mean insolation
flux of 1.2+0.3-0.2{PHI}⊕. This makes it one of the few
known planets receiving Earth-like insolation flux.
Description:
We reduced 206 available raw HARPS-N spectra through the YABI portal
hosted by the Centro Italiano Archivi Astronomici. YABI implements the
classical HARPS-N pipeline and computes CCFs for a given template
mask. We used an M2-type mask to obtain CCF RVs.
This data source contains the complete HARPS-N velocimetry that was
used in the paper.
Objects:
------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------
17 16 00.63 +11 03 27.6 GJ 3998 = TIC 459558974
------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
harpsn.dat 201 204 HARPS-N velocimetry of GJ 3998
--------------------------------------------------------------------------------
See also:
J/A+A/593/A117 : GJ 3998 RVs, S and Halpha indexes (Affer+, 2016)
Byte-by-byte Description of file: harpsn.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.12 d BJD Reduced Julian date (BJD-2400000)
20- 38 F19.12 m/s RVlbl Line-by-line radial velocity
40- 57 F18.16 m/s e_RVlbl Line-by-line radial velocity error
59- 77 F19.12 m/s RVccf Cross-correlation function radial velocity
79- 96 F18.16 m/s e_RVccf Cross-correlation function radial velocity error
98-115 F18.13 m/s FWHMccf Full width at half maximum
117-135 F19.16 m/s e_FWHMccf Full width at half maximum error
137-146 F10.8 --- SMW Mount Wilson S-index
148-157 F10.8 --- e_SMW Mount Wilson S-index error
159-168 F10.8 --- Halpha H-alpha indicator
170-179 F10.8 --- e_Halpha H-alpha indicator error
181-190 F10.8 --- NaI Na I indicator
192-201 F10.8 --- e_NaI Na I indicator error
--------------------------------------------------------------------------------
Acknowledgements:
Atanas Stefanov, atanas.stefanov(at)iac.es
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
Affer et al., Paper IX 2019A&A...622A.193A 2019A&A...622A.193A, Cat. J/A+A/622/A193
Gonzalez-Alvarez et al., Paper X 2019A&A...624A..27G 2019A&A...624A..27G
Pinamonti et al., Paper XI 2019A&A...625A.126P 2019A&A...625A.126P
Maldonado et al., Paper XII 2020A&A...644A..68M 2020A&A...644A..68M, Cat. J/A+A/644/A68
Gonzalez-Alvarez et al., Paper XIII 2021A&A...649A.157G 2021A&A...649A.157G
Maldonado et al., Paper XIV 2021A&A...651A..93M 2021A&A...651A..93M, Cat. J/A+A/651/A93
Pinamonti et al., Paper V 2022A&A...664A..65P 2022A&A...664A..65P, Cat. J/A+A/664/A65
(End) Patricia Vannier [CDS] 11-May-2025