J/A+A/669/A117 Mass-radius relationship of 34 Kepler planets (Leleu+, 2023)
Removing biases on the density of sub-Neptunes characterised via transit timing
variations. Update on the mass-radius relationship of 34 Kepler planets
Leleu A., Delisle J.-B., Udry S., Mardling R., Turbet M., Egger J.A.,
Alibert Y., Chatel G., Eggenberger P., Stalport M.
<Astron. Astrophys. 669, A117 (2023)>
=2023A&A...669A.117L 2023A&A...669A.117L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: planets and satellites: fundamental parameters -
methods: data analysis - techniques: photometric -
celestial mechanics - planets and satellites: general
Abstract:
Transit timing variations (TTVs) can provide useful information on
compact multi-planetary systems observed by transits by setting
constraints on the masses and eccentricities of the observed planets.
This is especially helpful when the host star is not bright enough for
a radial velocity (RV) follow-up. However, {in the past decade}, a
number of works have shown that TTV- characterised planets tend to
have lower densities than planets characterised on the basis of RVs.
Re-analysing 34 Kepler planets in the super-Earth to sub- Neptunes
range using the RIVERS approach, we show that at least some of these
discrepancies were due to the way transit timings were extracted from
the light curve, as a result of their tendency to underestimate the
TTV amplitudes. We recovered robust mass estimates (i.e. with low
prior dependency) for 23 of the planets. We compared these planets the
RV- characterised population and found that a large fraction of those
that previously had unusually low density estimates were adjusted,
allowing them to occupy a place on the mass-radius diagram much closer
to the bulk of known planets. However, a slight shift toward lower
densities remains, which could indicate that the compact
multi-planetary systems characterised by TTVs are indeed composed of
planets that are different from the bulk of the RV- characterised
population. These results are especially important in the context of
obtaining an unbiased view of the compact multi-planetary systems
detected by Kepler, TESS, and the upcoming PLATO mission.
Description:
We re-analysed a sample of 34 Kepler planets in the super-Earth to
mini-Neptune range in 15 multi-planetary systems. Most of these
planets were known to have TTVs, with transit timings available in
current databases Rowe et al. (2015ApJS..217...16R 2015ApJS..217...16R, Cat.
J/ApJS/217/16); Holczer et al. (2016ApJS..225....9H 2016ApJS..225....9H, Cat.
J/ApJS/225/9). These systems were previously characterised by fitting
these pre-extracted transit timings (e.g. Jontof-Hutter et al.
2016ApJ...820...39J 2016ApJ...820...39J; Hadden & Lithwick, 2017AJ....154....5H 2017AJ....154....5H, Cat.
J/AJ/154/5). Our analysis used the RIVERS method, which first
estimates the transit timings of the planets using the RIVERS.deep
algorithm (CNN-based image recognition; see Sect. 2.3), then uses a
photo-dynamical fit of the light curve (see Sect. 2.5).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 15 Stellar parameters
timings.dat 69 4578 Transit timings and errors extracted from
photo-dynamical fits
samp-2p.dat 225 3300 Samples of the photodynamic fits for 2-planets
systems, Jacobi orbital elements at
epoch 100.0 [BJD-2454833.0]
samp-3p.dat 330 900 Samples of the photodynamic fits for 3-planets
systems, Jacobi orbital elements at
epoch 100.0 [BJD-2454833.0]
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/AJ/159/280 : Gaia-Kepler stellar properties cat. I. KIC stars (Berger+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name, Kepler-NNN
12- 19 I8 --- KIC KIC identification number
20 A1 --- n_KIC [*] Note on KIC (1)
22- 27 F6.1 K Teff Effective temperature (2)
29- 33 F5.1 K e_Teff Effective temperature error (2)
35- 39 F5.3 Msun M* Star mass (2)
41- 45 F5.3 Msun e_M* Star mass error (2)
47- 51 F5.3 Rsun R* Star radius (2)
53- 57 F5.3 Rsun e_R* Star radius error (2)
59- 64 F6.4 Sun rho* Star density (2)
66- 71 F6.4 Sun e_rho* Star density error (2)
73- 78 A6 --- KOI KOI, KNNNNN
80- 81 A2 --- Samp [2p 3p] Sample with photodynamic fits (3)
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Note (1): Note as follows:
* = indicates that the parameters were updated, see sec. 2.2.
Note (2): Stellar parameters from Berger et al. (2020, Cat. J/AJ/159/280)
Note (3): 2p for samp-2p.dat, 3p for samp-3p.dat.
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Byte-by-byte Description of file: timings.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- KOI KOI of the transiting planet, KNNNNN.NN
11- 29 F19.14 d Date [100.38/1588.16] Median transit date,
BJD-2454833.0
31- 49 F19.14 d b_Date [100.38/1588.16] Date 0.15865 quantile,
BJD-2454833.0
51- 69 F19.14 d B_Date [100.39/1588.17] Date 0.84135 quantile,
BJD-2454833.0
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Byte-by-byte Description of file: samp-2p.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- KOI KOI, KNNNNN
8- 26 F19.15 deg lambda1 [9.25/319.64] Mean longitude 1
28- 46 F19.16 d P1 [5.72/15.09] Orbital period 1
48- 71 E24.17 --- ecw1 [-0.18/0.11] ecc1*cos(long of pericenter 1)
73- 96 E24.17 --- esw1 [-0.16/0.17] ecc1*sin(long of pericenter 1)
98-116 F19.16 --- logM1/M* [-5.81/-3.88] log10(m1/mstar)
118-136 F19.15 deg lambda2 [29.5/336.85] Mean longitude 2
138-155 F18.15 d P2 [8.98/25.76] Orbital period 2
157-180 E24.17 --- ecw2 [-0.12/0.13] ecc2*cos(long of pericenter 2)
182-205 E24.17 --- esw2 [-0.13/0.12] ecc2*sin(long of pericenter 2)
207-225 F19.16 --- logM2/M* [-5.64/-3.96] log10(m2/mstar)
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Byte-by-byte Description of file: samp-3p.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- KOI KOI, KNNNNN
8- 25 F18.14 deg lambda1 [62.61/210.45] Mean longitude 1
27- 44 F18.16 d P1 [5.48/8.15] Orbital period 1
46- 69 E24.17 --- ecw1 [-0.06/0.07] ecc1*cos(long of pericenter 1)
71- 94 E24.17 --- esw1 [-0.03/0.09] ecc1*sin(long of pericenter 1)
96-114 F19.16 --- logM1/M* [-5.06/-4.3] log10(M1/Mstar)
116-133 F18.14 deg lambda2 [67.53/337.48] Mean longitude 2
135-152 F18.15 d P2 [8.28/12.34] Orbital period 2
154-177 E24.17 --- ecw2 [-0.06/0.05] ecc2*cos(long of pericenter 2)
179-202 E24.17 --- esw2 [-0.04/0.06] ecc2*sin(long of pericenter 2)
204-222 F19.16 --- logM2/M* [-5.19/-4.34] log10(M2/Mstar)
224-241 F18.14 deg lambda3 [159.63/332.25] Mean longitude 3
243-260 F18.15 d P3 [11.9/19.02] Orbital period 3
262-285 E24.17 --- ecw3 [-0.08/0.06] ecc3*cos(long of pericenter 3)
287-310 E24.17 --- esw3 [-0.08/0.05] ecc3*sin(long of pericenter 3)
312-330 F19.16 --- logM3/M* [-7.0/-4.31] log10(M3/Mstar)
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Acknowledgements:
Adrien Leleu, Adrien.Leleu(at)unige.ch
(End) Patricia Vannier [CDS] 16-Jan-2023