J/A+A/673/A42 CHEOPS observations of WASP-47 (Nascimbeni+, 2023)
A new dynamical modeling of the WASP-47 system with CHEOPS observations.
Nascimbeni V., Borsato L., Zingales T., Piotto G., Pagano I., Beck M.,
Broeg C., Ehrenreich D., Hoyer S., Majidi F.Z., Granata V., Sousa S.G.,
Wilson T.G., Van Grootel V., Bonfanti A., Salmon S., Mustill A.J.,
Delrez L., Alibert Y., Alonso R., Anglada G., Barczy T., Barrado D.,
Barros S.C.C., Baumjohann W., Beck T., Benz W., Bergomi M., Billot N.,
Bonfils X., Brandeker A., Cabrera J., Charnoz S., Collier Cameron A.,
Csizmadia S., Cubillos P.E., Davies M.B., Deleuil M., Deline A.,
Demangeon O.D.S., Demory B.-O., Erikson A., Fortier A., Fossati L.,
Fridlund M., Gandolfi D., Gillon M., Gudel M., Isaak K.G., Kiss L.L.,
Laskar J., Lecavelier Des Etangs A., Lendl M., Lovis C., Luque R.,
Magrin D., Maxted P.F.L., Mordasini C., Olofsson G., Ottensamer R.,
Palle E., Peter G., Piazza D., Pollacco D., Queloz D., Ragazzoni R.,
Rando N., Ratti F., Rauer H., Ribas I., Santos N.C., Scandariato G.,
Segransan D., Simon A.E., Smith A.M.S., Steinberger M., Steller M.,
Szabo G.M., Thomas N., Udry S., Venturini J., Walton N.A., Wolter D.
<Astron. Astrophys. 673, A42 (2023)>
=2023A&A...673A..42N 2023A&A...673A..42N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: techniques: photometric - planets and satellites: detection -
planets and satellites: general
Abstract:
Among the hundreds of known hot Jupiters (HJs), only five have been
found to have companions on short-period orbits. Within this rare
class of multiple planetary systems, the architecture of WASP-47 is
unique, hosting an HJ (planet -b) with both an inner and an outer
sub-Neptunian mass companion (-e and -d, respectively) as well as an
additional non-transiting, long-period giant (-c). The small period
ratio between planets -b and -d boosts the transit time variation
(TTV) signal, making it possible to reliably measure the masses of
these planets in synergy with the radial velocity (RV) technique. In
this paper, we present new space- and ground- based photometric data
of WASP-47b and WASP-47-d, including 11 unpublished light curves from
the ESA mission CHEOPS. We analyzed the light curves in a homogeneous
way together with all the publicly available data to carry out a
global N-body dynamical modeling of the TTV and RV signals. We
retrieved, among other parameters, a mass and density for planet -d of
Md=15.5±0.8M⊕ and rhod=1.69±0.22g/cm3, which is in
good agreement with the literature and consistent with a Neptune-like
composition. For the inner planet (-e), we found a mass and density of
Me=9.0±0.5M⊕ and rhoe=8.1±0.5g/cm3, suggesting an
Earth-like composition close to other ultra- hot planets at similar
irradiation levels. Though this result is in agreement with previous
RV+TTV studies, it is not in agreement with the most recent RV
analysis (at 2.8σ), which yielded a lower density compatible
with a pure silicate composition. This discrepancy highlights the
still unresolved issue of suspected systematic offsets between RV and
TTV measurements. In this paper, we also significantly improve the
orbital ephemerides of all transiting planets, which will be crucial
for any future follow-up.
Description:
a) Photometric time series of WASP-47 obtained by CHEOPS and REM
during the transits of planets -b and -c. The provided flux for the
CHEOPS light curves corresponds to the roll-angle detrended normalized
flux; b) transit times of WASP-47b, -d, -e analyzed in the previous
work (Tables A.1 to A.3 and A.5 of the paper).
Objects:
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RA (2000) DE Designation(s)
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22 04 48.72 -12 01 07.9 WASP-47 = 1SWASP J220448.72-120107.8
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lcs.dat 138 4321 Light curves of WASP-47b and WASP-47d
t0s.dat 71 137 Transit times of WASP-47b, WASP-47d and WASP-47e
predicted by our dynamic model
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See also:
J/A+A/586/A93 : WASP41 & WASP47 photometric and RV data (Neveu-VanMalle+, 216)
J/AJ/154/237 : HARPS-N radial velocities of WASP-47 (Vanderburg+, 2017)
Byte-by-byte Description of file: lcs.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d Time Time of the observation, BJD-TDB standard
20- 37 F18.16 --- Flux Detrended flux, normalized
39- 61 E23.15 --- e_Flux 1-sigma error on the detrended flux
63- 80 F18.16 --- Model Best-fit PyORBIT model
82-105 E24.16 --- Res Flux residuals from the best-fit model
107-120 F14.6 --- T0 Best-fit transit time T0, for stacking
122-123 I2 --- N Numerical ID, for plotting
125-126 A2 --- Planet [-b -d] Name of the planet (-b or -d)
128-138 A11 --- Id ID of the corresponding light curve (1)
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Note (1): cheopsb01-cheopsb10 for CHEOPS -b observations,
cheopsc01 for CHEOPS -d observations,
rem_g, rem_i and rem_r for REM -b observations.
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Byte-by-byte Description of file: t0s.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d T0 Central transit time T0, BJD-TDB standard
16- 39 E24.16 d s_T0 Symmetrized 1-sigma error on T0
41- 50 E10.2 d e_T0 [] Lower 1-sigma error bar on T0
52- 61 E10.2 d E_T0 Upper 1-sigma error bar on T0
63- 68 A6 --- Inst Instrument (1)
70- 71 A2 --- Planet [-b -d -e] Name of the planet (-b, -d, -e)
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Note (1): Instruments are CHEOPS, ETD, K2, TESS, REM_g, REM_r and REM_i.
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Acknowledgements:
Valerio Nascimbeni, valerio.nascimbeni(at)inaf.it
(End) Patricia Vannier [CDS] 09-Sep-2024