J/A+A/679/A92 TOI-561 b CHEOPS lightcurves (Patel+, 2023)
CHEOPS and TESS view of the ultra-short period super-Earth TOI-561 b.
Patel J.A., Egger J.A., Wilson T.G., Bourrier V., Carone L., Beck M.,
Ehrenreich D., Sousa S.G., Benz W., Brandeker A., Deline A., Alibert Y.,
Lam K., Lendl M., Alonso R., Anglada G., Barczy T., Barrado D.,
Barros S.C.C., Baumjohann W., Beck T., Billot N., Bonfils X., Broeg C.,
Busch M.-D., Cabrera J., Charnoz S., Collier Cameron A., Csizmadia Sz.,
Davies M.B., Deleuil M., Delrez L., Demangeon O.D.S., Demory B.-O.,
Erikson A., Fortier A., Fossati L., Fridlund M., Gandolfi D., Gillon M.,
Guedel M., Heng K., Hoyer S., Isaak K.G., Kiss L.L., Kopp E., Laskar J.,
Lecavelier des Etangs A., Lovis C., Magrin D., Maxted P.F.L., Nascimbeni V.,
Olofsson G., Ottensamer R., Pagano I., Palle E., Peter G., Piotto G.,
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., Steller M., Szabo Gy.M., Thomas N., Udry S., Ulmer B.,
Van Grootel V., Viotto V., Walton N.A.
<Astron. Astrophys. 679, A92 (2023)>
=2023A&A...679A..92P 2023A&A...679A..92P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: techniques: photometric -
planets and satellites: terrestrial planets -
planets and satellites: composition -
planets and satellites: atmospheres -
planets and satellites: individual: TOI-561 b
Abstract:
Ultra-short period planets (USPs) are a unique class of super-Earths
with an orbital period of less than a day and hence subject to intense
radiation from their host star. These planets cannot retain a
primordial H/He atmosphere, and most of them are indeed consistent
with being bare rocky cores. A few USPs, however, show evidence for a
heavyweight envelope, which could be a water layer resilient to
evaporation, or a secondary metal-rich atmosphere sustained by
outgassing of the molten, volcanic surface. Much thus remains to be
learned about the nature and formation of USPs.
The prime goal of the present work is to refine the bulk planetary
properties of the recently discovered TOI-561 b, through the study of
its transits and occultations. This is crucial to understand the
internal structure of this USP and assess the presence of an
atmosphere. Methods. We obtained ultra-precise transit photometry of
TOI-561 b with CHEOPS, and performed a joint analysis of this data
along with three archival visits from CHEOPS and four TESS sectors.
Our analysis of TOI-561 b transit photometry put strong constraints on
its properties. In particular, we restrict the uncertainties on the
planetary radius at ∼2% retrieving Rp=1.42±0.02R⊕. This
result informs our internal structure modelling of the planet, which
shows that the observations are consistent with negligible H/He
atmosphere, however requiring other lighter materials, in addition to
pure iron core and silicate mantle to explain the observed density. We
find that this can be explained by the inclusion of a water layer in
our model. Additionally, we run a grid of forward models with a
water-enriched atmosphere to explain the transit radius. We searched
for variability in the measured Rp/R* over time, which could trace
changes in the structure of the planetary envelope. No temporal
variations are however recovered within the present data precision. In
addition to the transit event, we tentatively detect occultation
signal in the TESS data with an eclipse depth
L=27.40+10.87-11.35ppm. We use models of outgassed atmospheres
from the literature to explain this eclipse signal. We find that the
thermal emission from the planet can mostly explain the observation.
Based on this, we predict that near/mid-infrared observations with the
James Webb Space Telescope should be able to detect silicate species
in the atmosphere of the planet. This could also reveal important
clues about the planetary interior and help disentangle planet
formation and evolution models.
Description:
Raw and detrended CHEOPS lightcurves of 13 transits of TOI-561 b.
Objects:
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RA (2000) DE Designation(s)
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09 52 44.54 +06 12 58.9 TOI-561 = TYC 243-1528-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 277 2338 Raw and detrended CHEOPS lightcurves of
13 transits of TOI-561 b
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See also:
J/MNRAS/511/4551 : TOI-561 CHEOPS light curves (Lacedelli+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d Time Time (BJD)
20- 37 F18.16 --- Flux Normalised raw flux
39- 60 F22.20 --- e_Flux 1-sigma uncertainty in Flux
62- 82 F21.17 deg Roll Roll angle
84-101 F18.14 pix Xc x-centroid position
103-120 F18.14 pix Yc y-centroid position
122-139 F18.14 --- BG Background
141-163 E23.17 --- U1 U1 component of PSF photometry
165-188 E24.17 --- U2 U2 component of PSF photometry
190-213 E24.17 --- U3 ?=0 U3 component of PSF photometry (1)
215-235 F21.19 --- U4 ?=0 U4 component of PSF photometry (1)
237-254 F18.16 --- Fluxdet Detrended normalised flux
256-277 F22.20 --- e_Fluxdet 1-sigma uncertainty in Fluxdet
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Note (1): Components of PSF photometry are replaced by 0.0 when they were
not available.
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Acknowledgements:
Jayshil A. Patel, jayshil.patel(at)astro.su.se
(End) Patricia Vannier [CDS] 21-Aug-2023