J/A+A/678/A200 TOI-178 raw and detrended photometry (Delrez+, 2023)
Refining the properties of the TOI-178 system with CHEOPS and TESS.
Delrez L., Leleu A., Brandeker A., Gillon M., Hooton M.J.,
Collier Cameron A., Deline A., Fortier A., Queloz D., Bonfanti A.,
Van Grootel V., Wilson T.G., Egger J.A., Alibert Y., Alonso R., Anglada G.,
Asquier J., Barczy T., Barrado y Navascues D., Barros S.C.C., Baumjohann W.,
Beck M., Beck T., Benz W., Billot N., Bonfils X., Borsato L., Broeg C.,
Buder M., Cabrera J., Cessa V., Charnoz S., Csizmadia Sz., Cubillos P.E.,
Davies M.B., Deleuil M., Demangeon O.D.S., Demory B.-O., Ehrenreich D.,
Erikson A., Fossati L., Fridlund M., Gandolfi D., Guedel M., Hasiba J.,
Hoyer S., Isaak K.G., Jenkins J.M., Kiss L.L., Laskar J., Latham D.W.,
Lecavelier des Etangs A., Lendl M., Lovis C., Luque R., Magrin D.,
Maxted P.F.L., Mordasini C., Nascimbeni V., Olofsson G., Ottensamer R.,
Pagano I., Palle E., Peter G., Piotto G., Pollacco D., Ragazzoni R.,
Rando N., Rauer H., Ribas I., Ricker G., Santos N.C., Scandariato G.,
Seager S., Segransan D., Simon A.E., Smith A.M.S., Sousa S.G., Steller M.,
Szabo Gy.M., Thomas N., Udry S., Vanderspek R., Venturini J., Viotto V.,
Walton N.A., Winn J.N.
<Astron. Astrophys. 678, A200 (2023)>
=2023A&A...678A.200D 2023A&A...678A.200D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: planetary systems - stars: individual: TOI-178 -
techniques: photometric
Abstract:
The TOI-178 system consists of a nearby late K-dwarf transited by six
planets in the super-Earth to mini-Neptune regime, with radii ranging
from ∼1.1 to 2.9 R_⊕ and orbital periods between 1.9 and 20.7
days. All planets but the innermost one form a chain of Laplace
resonances. Mass estimates derived from a preliminary radial velocity
(RV) dataset suggest that the planetary densities do not decrease in a
monotonic way with the orbital distance to the star, contrary to what
one would expect based on simple formation and evolution models.
To improve the characterisation of this key system and prepare for
future studies (in particular with JWST), we performed a detailed
photometric study based on 40 new CHEOPS visits, one new TESS sector,
and previously published CHEOPS, TESS, and NGTS data.
First we updated the parameters of the host star using the new
parallax from Gaia EDR3. We then performed a global analysis of the
100 transits contained in our data to refine the physical and orbital
parameters of the six planets and study their transit timing
variations (TTVs). We also used our extensive dataset to place
constraints on the radii and orbital periods of potential additional
transiting planets in the system.
Our analysis significantly refines the transit parameters of the six
planets, most notably their radii, for which we now obtain relative
precisions of ≲3%, with the exception of the smallest planet, b, for
which the precision is 5.1%. Combined with the RV mass estimates, the
measured TTVs allow us to constrain the eccentricities of planets $c$
to $g$, which are found to be all below 0.02, as expected from
stability requirements. Taken alone, the TTVs also suggest a higher
mass for planet $d$ than that estimated from the RVs, which had been
found to yield a surprisingly low density for this planet. However,
the masses derived from the current TTV dataset are very
prior-dependent, and further observations, over a longer temporal
baseline, are needed to deepen our understanding of this iconic
planetary system.
Description:
CHEOPS, TESS and NGTS raw and detrended photometry.
Objects:
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RA (2000) DE Designation(s)
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00 29 12.30 -30 27 13.4 TOI-178 = TIC 251848941
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cheopsr.dat 207 10339 CHEOPS raw photometry
cheopsd.dat 59 10339 CHEOPS detrended photometry
tessr.dat 42 11606 TESS raw photometry
tessd.dat 59 11606 TESS detrended photometry
ngtsr.dat 47 26783 NGTS raw photometry
ngtsd.dat 59 26783 NGTS detrended photometry
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Byte-by-byte Description of file: cheopsr.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date (TDB)
20- 37 F18.16 --- Flux Raw normalised flux
39- 59 F21.19 --- e_Flux Error on the raw normalised flux
61- 81 F21.19 rad Roll Roll angle
83-105 E23.18 --- SinRoll Sine of the roll angle
107-128 F22.19 --- CossRoll Cosine of the roll angle
130-149 F20.15 e- Bck Background
151-168 F18.14 pix Xcen X-centroid position
170-187 F18.14 pix Ycen Y-centroid position
189-207 F19.15 degC Temp Telescope tube temperature
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Byte-by-byte Description of file: tessr.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date (TDB)
20- 29 F10.8 --- Flux Detrended normalised flux
31- 42 F12.10 --- e_Flux Error on the detrended normalised flux
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Byte-by-byte Description of file: ngtsr.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d BJD Barycentric Julian date (TDB)
18- 27 F10.8 --- Flux Raw normalised flux
29- 38 F10.8 --- e_Flux Error on the raw normalised flux
40- 47 F8.6 --- Airm Airmass
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Byte-by-byte Description of file: cheopsd.dat ngtsd.dat tessd.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date (TDB)
20- 37 F18.16 --- Flux Detrended normalised flux
39- 59 F21.19 --- e_Flux Error on the detrended normalised flux
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Acknowledgements:
Laetitia Delrez, ldelrez(at)uliege.be
(End) Patricia Vannier [CDS] 02-Oct-2023