J/A+A/624/A123 Gl 49 radial velocities and activity indicators (Perger+, 2019)
Gliese 49: activity evolution and detection of a super-Earth.
A HADES and CARMENES collaboration.
Perger M., Scandariato G., Ribas I., Morales J.C., Affer L., Azzaro M.,
Amado P.J., Anglada-Escude G., Baroch D., Barrado D., Bauer F.F.,
Bejar V.J.S., Caballero J.A., Cortes-Contreras M., Damasso M., Dreizler S.,
Gonzalez-Cuesta L., Gonzalez Hernandez J.I., Guenther E.W., Henning T.,
Herrero E., Jeffers S.V., Kaminski A., Kuerster M., Lafarga M., Leto G.,
Lopez-Gonzalez M.J., Maldonado J., Micela G., Montes D., Pinamonti M.,
Quirrenbach A., Rebolo R., Reiners A., Rodriguez E., Rodriguez-Lopez C.,
Schmitt J.H.M.M., Sozzetti A., SuarezMascareno A., Toledo-Padron B.,
Zanmar Sanchez R., Zapatero Osorio M.R., Zechmeister M.
<Astron. Astrophys. 624, A123 (2019)>
=2019A&A...624A.123P 2019A&A...624A.123P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Spectroscopy
Keywords: planetary systems - techniques: radial velocities -
stars: late-type - stars: activity - stars: individual: Gl 49 -
methods: data analysis
Abstract:
Small planets around low-mass stars often show orbital periods in a
range that corresponds to the temperate zones of their host stars
which are therefore of prime interest for planet searches. Surface
phenomena such as spots and faculae create periodic signals in radial
velocities and in observational activity tracers in the same range, so
they can mimic or hide true planetary signals.
We aim to detect Doppler signals corresponding to planetary
companions, determine their most probable orbital configurations, and
understand the stellar activity and its impact on different datasets.
We analyzed 22 years of data of the M1.5V-type star Gl 49 (BD+61 195)
including HARPS-N and CARMENES spectrographs, complemented by APT2 and
SNO photometry. Activity indices are calculated from the observed
spectra, and all datasets are analyzed with periodograms and noise
models. We investigated how the variation of stellar activity imprints
on our datasets. We further tested the origin of the signals and
investigate phase shifts between the different sets. To search for the
best-fit model we maximize the likelihood function in a Markov chain
Monte Carlo approach.
As a result of this study, we are able to detect the super-Earth
Gl 49b with a minimum mass of 5.6M{earth}. It orbits its host star
with a period of 13.85d at a semi-major axis of 0.090au and we
calculate an equilibrium temperature of 350K and a transit probability
of 2.0%. The contribution from the spot-dominated host star to the
different datasets is complex, and includes signals from the stellar
rotation at 18.86d, evolutionary timescales of activity phenomena at
40-80d, and a long-term variation of at least four years.
Description:
Radial velocity and activity indicator time-series data of Gl 49 from
HIRES, HARPS-N, and CARMENES instruments.
We obtained 137 RVs from optical spectra of the HADES program. They
were observed over six seasons (S1 to S6) between 3 Sep 2012 and 11
Oct 2017 with HARPS-N.
We obtained spectroscopic observations with the CARMENES instrument,
installed since 2015 at the 3.51m telescope of the Calar Alto
Observatory in Spain.
Gl 49 was also observed with the HIRES instrument, installed since the
late 1990s at the Keck I telescope located in Hawaii, USA.
Objects:
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RA (2000) DE Designation(s)
---------------------------------------------
01 02 38.87 +62 20 42.2 Gl 49 = BD+61 195
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 126 238 Radial velocity and activity indicator
time-series data of Gl 49
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 d BJD Barycentric Julian date (BJD-2450000)
11- 18 F8.4 m/s RV Radial velocity
20- 25 F6.4 m/s e_RV ? Radial velocity uncertainty
27- 32 F6.4 --- CaHK/CaIRT ? CaHK/CaIRT index for HARPS-N/CARMENES
34- 39 F6.4 --- e_CaHK/CaIRT ? CaHK/CaIRT index uncertainty
41- 46 F6.4 --- Ha ? H-alpha index
48- 53 F6.4 --- e_Ha ? H-alpha index uncertainty
55- 60 F6.4 --- NaI ? NaI index
62- 67 F6.4 --- e_NaI ? NaI index uncertainty
69- 73 F5.3 km/s FWHM ? FWHM of CCF
75- 79 F5.3 km/s e_FWHM ? FWHM index uncertainty
81- 86 F6.3 % CON ? Contrast of CCF
88- 92 F5.3 % e_CON ? CON index uncertainty
94- 99 F6.2 m/s BIS ? Bisector inverse slope of CCF
101-104 F4.2 m/s e_BIS ? BIS index uncertainty
106-110 F5.1 --- CRX ? Chromatic index (in m/s/Np unit)
112-115 F4.1 --- e_CRX ? CRX index uncertainty (in m/s/Np unit)
117-124 A8 --- Inst Instrument (HARPS-N, HIRES or CARMENES)
125-126 A2 --- Season Season (S0-S6)
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Acknowledgements:
Manuel Perger, map(at)posteo.de
(End) M. Perger [ICE-CSIC, IEEC, Catalonia], P. Vannier [CDS] 18-Mar-2019