J/A+A/658/A75 MASCARA-1 b occultation and transit light curves (Hooton+, 2022)
Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and
reveal a hint of dayside reflection.
Hooton M.J., Hoyer S., Kitzmann D., Morris B.M., Smith A.M.S.,
Collier Cameron A., Futyan D., Maxted P.F.L., Queloz D., Demory B.-O.,
Heng K., Lendl M., Cabrera J., Csizmadia Sz., Deline A., Parviainen H.,
Salmon S., Sulis S., Wilson T.G., Bonfanti A., Brandeker A.,
Demangeon O.D.S., Oshagh M., Persson C.M., Scandariato G., Alibert Y.,
Alonso R., Anglada Escude G., Barczy T., Barrado D., Barros S.C.C.,
Baumjohann W., Beck M., Beck T., Benz W., Billot N., Bonfils X.,
Bourrier V., Broeg C., Busch M.-D., Charnoz S., Davies M.B., Deleuil M.,
Delrez L., Ehrenreich D., Erikson A., Farinato J., Fortier A., Fossati L.,
Fridlund M., Gandolfi D., Gillon M., Guedel M., Isaak K.G., Jones K.,
Kiss L., Laskar J., Lecavelier des Etangs A., Lovis C., Luntzer A.,
Magrin D., Nascimbeni V., Olofsson G., Ottensamer R., Pagano I., Palle E.,
Peter G., Piotto G., Pollacco D., Ragazzoni R., Rando N., Ratti F.,
Rauer H., Ribas I., Santos N.C., Segransan D., Simon A.E., Sousa S.G.,
Steller M., Szabo Gy.M., Thomas N., Udry S., Ulmer B., Van Grootel V.,
Walton N.A.
<Astron. Astrophys. 658, A75 (2022)>
=2022A&A...658A..75H 2022A&A...658A..75H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry
Keywords: techniques: photometric - planets and satellites: atmospheres -
planets and satellites: physical evolution -
planets and satellites: individual: MASCARA-1 b
Abstract:
The light curves of tidally locked hot Jupiters transiting
fast-rotating, early-type stars are a rich source of information about
both the planet and star, with full-phase coverage enabling a detailed
atmospheric characterisation of the planet. Although it is possible to
determine the true spin-orbit angle Psi -- a notoriously difficult
parameter to measure -- from any transit asymmetry resulting from
gravity darkening induced by the stellar rotation, the correlations
that exist between the transit parameters have led to large
disagreements in published values of Psi for some systems. We aimed to
study these phenomena in the light curves of the ultra-hot Jupiter
MASCARA-1 b, which is characteristically similar to well-studied
contemporaries such as KELT-9 b and WASP-33 b. We obtained optical
CHaracterising ExOPlanet Satellite (CHEOPS) transit and occultation
light curves of MASCARA-1 b, and analysed them jointly with a
Spitzer/IRAC 4.5 micron full-phase curve to model the asymmetric
transits, occultations, and phase-dependent flux modulation. For the
latter, we employed a novel physics-driven approach to jointly fit the
phase modulation by generating a single 2D temperature map and
integrating it over the two bandpasses as a function of phase to
account for the differing planet-star flux contrasts. The reflected
light component was modelled using the general ab initio solution for
a semi-infinite atmosphere. When fitting the CHEOPS and Spitzer
transits together, the degeneracies are greatly diminished and return
results consistent with previously published Doppler tomography.
Placing priors informed by the tomography achieves even better
precision, allowing a determination of Psi=72.1+2.5-2.4deg. From
the occultations and phase variations, we derived dayside and
nightside temperatures of 3062+66-68K and 1720±330K,
respectively. Our retrieval suggests that the dayside emission
spectrum closely follows that of a blackbody. As the CHEOPS
occultation is too deep to be attributed to blackbody flux alone, we
could separately derive geometric albedo Ag=0.166+0.066-0.068
and spherical albedo As=0.266+0.097-0.100 from the CHEOPS data,
and Bond albedo AB=0.053+0.083-0.101 from the Spitzer phase
curve. Although small, the Ag and As indicate that MASCARA-1 b is more
reflective than most other ultra-hot Jupiters, where H- absorption
is expected to dominate. Where possible, priors informed by Doppler
tomography should be used when fitting transits of fast-rotating
stars, though multi-colour photometry may also unlock an accurate
measurement of Psi. Our approach to modelling the phase variations at
different wavelengths provides a template for how to separate thermal
emission from reflected light in spectrally resolved James Webb Space
Telescope phase curve data.
Description:
We present photometric light curves observed by CHEOPS, containing
three occultations and two transits of MASCARA-1 b. Occultation 1 is
not included in the joint analysis, and is analysed separately in
section 3.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
occ1.dat 281 885 MASCARA-1 b occultation 1 light curve
occ2.dat 275 890 MASCARA-1 b occultation 2 light curve
occ3.dat 275 939 MASCARA-1 b occultation 3 light curve
trans1.dat 275 547 MASCARA-1 b transit 1 light curve
trans2.dat 275 817 MASCARA-1 b transit 2 light curve
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See also:
J/A+A/606/A73 : MASCARA-1 b (HD201585) light curves and spectra (Talens+, 2017)
Byte-by-byte Description of file: occ1.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- 33 F16.14 --- Flux Normalised flux
35- 54 F20.18 --- e_Flux Normalised flux error
56- 72 F17.14 --- Xoffset X offset from average
74- 90 F17.14 --- Yoffset Y offset from average
92-107 F16.8 --- background Detector background
109-128 F20.18 --- contam Predicted contamination from nearby PSFs
130-150 F21.19 --- smear Predicted smearing contamination
152-167 F16.12 --- Xcent X centroid position
169-184 F16.12 --- Ycent Y centroid position
186-201 F16.12 deg RollAngle Spacecraft roll angle
203-224 F22.19 --- glinty Y offset detrended "glint" function
226-241 F16.14 --- Fluxdetrendy Y offset detrended normalised flux
243-264 F22.19 --- glintbg Time detrended "glint" function
266-281 F16.14 --- Fluxdetrendbg Time detrended normalised flux
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Byte-by-byte Description of file: occ2.dat occ3.dat trans1.dat trans2.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 Normalised flux
39- 60 F22.20 --- e_Flux Normalised flux error
62- 79 F18.15 --- Xoffset X offset from average
81- 97 F17.14 --- Yoffset Y offset from average
99-127 F29.20 --- background Detector background
129-150 F22.20 --- contam Predicted contamination from nearby PSFs
152-173 E22.19 --- smear Predicted smearing contamination
175-192 F18.14 --- Xcent X centroid position
194-210 F17.13 --- Ycent Y centroid position
212-232 F21.17 deg RollAngle Spacecraft roll angle
234-256 E23.19 --- glint Roll angle-dependent "glint" function
258-275 F18.16 --- Fluxdetrend Detrended normalised flux
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Acknowledgements:
Matthew J. Hooton, matthew.hooton(at)unibe.ch
(End) Patricia Vannier [CDS] 09-Dec-2021