J/A+A/657/A68 HD 137496 system discovery (Silva+, 2022)
The HD 137496 system: A dense hot super Mercury and a cold Jupiter.
Silva T.A., Demangeon O.D.S, Barros S.C.C., Armstrong D.J., Otegi J.F.,
Bossini D., Delgado Mena E., Sousa S.G., Adibekyan V., Nielsen L.D.,
Dorn C., Lillo-Box J., Santos N.C., Hoyer S., Stassun K.G., Almenara J.M.,
Bayliss D., Barrado D., Boisse I., Brown D.J.A., Diaz R.F., Dumusque X.,
Figueira P., Hadjigeorghiou A., Hojjatpanah S., Mousis O., Osborn A.,
Santerne A., Strom P.A., Udry S., Wheatley P.J.
<Astron. Astrophys. 657, A68 (2022)>
=2022A&A...657A..68S 2022A&A...657A..68S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Abundances ;
Radial velocities ; Photometry ; Optical
Keywords: planets and satellites: composition -
planets and satellites: detection - stars: individual: HD 137496 -
techniques: photometric - techniques: radial velocities
Abstract:
Most of the currently known planets are small worlds with radii
between that of the Earth and Neptune. The characterization of planets
in this regime shows a large diversity in compositions and system
architectures, with distributions hinting at a multitude of formation
and evolution scenarios. However, many planetary populations, such as
high-density planets, are significantly under-sampled limiting our
understanding on planet formation and evolution.
NCORES is a large observing program conducted on the HARPS
high-resolution spectrograph which aims to confirm the planetary status
and to measure the masses of small transiting planetary candidates
detected by transit photometry surveys in order to constrain their
internal composition.Methods.Using photometry from the K2 satellite
and radial velocities measured with the HARPS and CORALIE
spectrographs, we search for planets around the bright (Vmag=10) and
slightly evolved Sun-like star HD 137496.
We precisely estimate the stellar parameters,
M*=1.035±0.022M☉, R*= 1.587±0.028R☉,
Teff=5799±61K,together with the chemical composition (e.g.
[Fe/H]=-0.027±0.040dex) of the slightly evolved star. We detect two
planets orbiting HD 137496. The inner planet, HD 137496 b, is a
super-Mercury (an Earth-sized planet with the density of Mercury) with
a mass of Mb=4.04±0.55M☉), a radius of
Rb=1.31+0.06-0.05R☉ and a density of
ρb=10.49+2.08-1.82g/cm3. From interior modeling analysis
we find that the planet is composed mainly of iron, with the core
representing over 70% of the planet's mass
(Mcore/Mtotal=0.73+0.11-0.12). The outer planet, HD 137496 c, is
an eccentric (e=0.477±0.004), long period (P=479.9+1.0-1.1days)
giant planet (Mc*sinic=7.66±0.11M{Jup}) for which we do not detect
a transit.
HD 137496 b is one of the few super-Mercuries detected to date. The
accurate characterization reported here enhances its role as a key
target to better understand the formation and evolution of planetary
systems. The detection of an eccentric long period giant companion also
reinforces the link between the presence of small transiting inner
planets and long period gas giants.
Description:
We present the observational data of HD 137496 used for the analysis
presented in the paper. Namely the rvs and stellar activity indicators
measured with HARPS and CORALIE (Table 1 in the paper) and the
photometric data from K2 after PCA detrending and from the POLAR
pipeline (Table A.1 in the paper).
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
15 26 58.07 -16 30 31.69 HD 137496 = BD-15 4106
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
rv.dat 214 172 HD 137496 radial velocities and stellar activity
indicators measured with HARPS and CORALIE
(table 1)
photom.dat 80 3656 HD 137496 photometric data from K2 after PCA
detrending and from the POLAR pipeline (table A1)
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Byte-by-byte Description of file: rv.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.12 d Time Time of the measurement, UTC (BJD-2400000)
20- 31 F12.6 m/s RV Radial velocity
33- 41 F9.6 m/s e_RV Uncertainty on the radial velocity (1 sigma)
43- 53 F11.6 m/s FWHM Full Width at Half Maximum (FWHM)
55- 63 F9.6 m/s e_FWHM Uncertainty on the FWHM (1 sigma)
65- 74 F10.6 m/s BisSpan Bisector span
76- 84 F9.6 m/s e_BisSpan Uncertainty on the bisector span (1 sigma)
86- 94 F9.6 --- Contrast Constrast
96-103 F8.6 --- e_Contrast Uncertainty on the contrast (1 sigma)
105-112 F8.6 --- Ha Hα index
114-121 F8.6 --- e_Ha Uncertainty on the Hα index (1 sigma)
123-130 F8.6 --- Na Na index
132-139 F8.6 --- e_Na Uncertainty on the Na index (1 sigma)
141-148 F8.6 --- Ca Ca index
150-157 F8.6 --- e_Ca ?=- Uncertainty on the Ca index (1 sigma)
159-166 F8.6 --- RHK ?=- Activity index RHK
168-175 F8.6 --- e_RHK ?=- Uncertainty on the activity index RHK
(1 sigma)
177-184 F8.6 --- SMW ?=- Mount Wilson S-index
186-193 F8.6 --- e_SMW ?=- Uncertainty on the Mount Wilson S-index
(1 sigma)
197-206 F10.6 m/s BERV Barycentric Earth Radial Velocity
208-214 A7 --- Inst [HARPS CORALIE] Instrument used
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 18 F18.12 d Time Time of the measurement, UTC (BJD-2400000)
20- 28 F9.1 e-/s FluxK2 ?=- Flux from the K2 PDCsap detrended
lightcurve
30- 38 F9.6 e-/s e_FluxK2 ?=- Error in the flux from the K2 PDCsap
detrended lightcurve
40- 57 F18.16 --- FluxPOLAR Flux from the POLAR detrended lightcurve
59- 80 E22.16 --- e_FluxPOLAR Error in the flux from the POLAR
detrended lightcurve
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Acknowledgements:
Tomas Silva, Tomas.Silva(at)astro.up.pt
(End) Patricia Vannier [CDS] 27-Oct-2021