J/A+A/668/A93 CHEOPS photometry of KELT-1 (Parviainen+, 2022)
CHEOPS finds KELT-1b darker than expected in visible light Discrepancy between
the CHEOPS and TESS eclipse depths.
Parviainen H., Wilson T.G., Lendl M., Kitzmann D., Palle E., Serrano L.M.,
Meier Valdes E., Benz W., Deline A., Ehrenreich D., Guterman P., Heng K.,
Demangeon O.D.S., Bonfanti A., Salmon S., Singh V., Santos N.C.,
Sousa S.G., Alibert Y., Alonso R., Anglada G., Barczy T.,
Barrado Y Navascues D., Barros S.C.C., Baumjohann W., Beck M., Beck T.,
Billot N., Bonfils X., Brandeker A., Broeg C., Cabrera J., Charnoz S.,
Collier Cameron A., Corral Van Damme C., Csizmadia Sz., Davies M.B.,
Deleuil M., Delrez L., Demory B.-O., Erikson A., Farinato J., Fortier A.,
Fossati L., Fridlund M., Gandolfi D., Gillon M., Gudel M., Hoyer S.,
Isaak K.G., Kiss L.L., Kopp E., Laskar J., Lecavelier des Etangs A.,
Lovis C., Magrin D., Maxted P.F.L., Mecina M., Nascimbeni V., Olofsson G.,
Ottensamer R., Pagano I., Peter G., Piazza D., Piotto G., Pollacco D.,
Queloz D., Ragazzoni R., Rando N., Rauer H., Ribas I., Scandariato G.,
Segransan D., Simon A.E., Smith A.M.S., Steller M., Szabo G.M., Thomas N.,
Udry S., Van Grootel V., Walton N.A.
<Astron. Astrophys., 668, A93 (2022)>
=2022A&A...668A..93P 2022A&A...668A..93P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: stars: individual: KELT-1 - brown dwarfs - planetary systems -
stars: atmospheres - methods: observational
Abstract:
Recent studies based on photometry from the Transiting Exoplanet
Survey Satellite (TESS) have suggested that the dayside of KELT-1b, a
strongly irradiated brown dwarf, is significantly brighter in visible
light than what would be expected based on Spitzer observations in the
infrared. We observed eight eclipses of KELT-1b with CHaracterising
ExOPlanet Satellite (CHEOPS) to measure its dayside brightness
temperature in the bluest passband observed so far, and we jointly
modelled the CHEOPS photometry with the existing optical and
near-infrared photometry from TESS, LBT, CFHT, and Spitzer. Our
modelling has led to a self-consistent dayside spectrum for KELT-1b
covering the CHEOPS, TESS, H, Ks, and Spitzer IRAC 3.6 and 4.5um
bands, where our TESS, H, Ks, and Spitzer band estimates largely agree
with the previous studies. However, we discovered a strong discrepancy
between the CHEOPS and TESS bands. The CHEOPS observations yield a
higher photometric precision than the TESS observations, but they do
not show a significant eclipse signal, while a deep eclipse is
detected in the TESS band. The derived TESS geometric albedo of
0.36-0.13+0.12 is difficult to reconcile with a CHEOPS geometric
albedo that is consistent with zero because the two passbands have
considerable overlap. Variability in cloud cover caused by the
transport of transient nightside clouds to the dayside could provide
an explanation for reconciling the TESS and CHEOPS geometric albedos,
but this hypothesis needs to be tested by future observations.
Description:
We present CHEOPS photometry of KELT-1b containing eight occultations.
Objects:
----------------------------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------------------------
23 58 53.15 +39 06 20.11 KELT-1 = TYC 2785-2130-1 = 2MASS J00012691+3923017
----------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
visit1.dat 682 193 Photometry for CHEOPS visit 1 (11 components)
visit2.dat 682 191 Photometry for CHEOPS visit 2 (20 components)
visit3.dat 682 217 Photometry for CHEOPS visit 3 (23 components)
visit4.dat 682 200 Photometry for CHEOPS visit 4 (19 components)
visit5.dat 682 244 Photometry for CHEOPS visit 5 (22 components)
visit6.dat 682 212 Photometry for CHEOPS visit 6 (11 components)
visit7.dat 682 223 Photometry for CHEOPS visit 7 (15 components)
visit8.dat 682 202 Photometry for CHEOPS visit 8 (27 components)
--------------------------------------------------------------------------------
See also:
https://github.com/hpparvi/cheops_kelt_1 : Paper GitHub repository.
Byte-by-byte Description of file: visit?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.10 --- BJD Time of mid-exposure (BJD)
20- 37 F18.16 --- Flux [0.99/1.01] Normalized flux
39- 56 F18.16 --- e_Flux [0.0/0.01] Normalized flux uncertainty
58- 80 E23.17 --- theta0 PSF component 0
82-103 E22.16 --- theta1 PSF component 1
105-126 E22.16 --- theta2 PSF component 2
128-149 E22.16 --- theta3 PSF component 3
151-172 E22.16 --- theta4 PSF component 4
174-195 E22.16 --- theta5 PSF component 5
197-219 E23.17 --- theta6 PSF component 6
221-239 F19.16 --- theta7 PSF component 7
241-262 E22.16 --- theta8 PSF component 8
264-285 E22.16 --- theta9 PSF component 9
287-308 E22.16 --- theta10 PSF component 10
310-331 E22.16 --- theta11 PSF component 11
333-355 E23.17 --- theta12 ? PSF component 12
357-378 E22.16 --- theta13 ? PSF component 13
380-402 E23.17 --- theta14 ? PSF component 14
404-422 F19.16 --- theta15 ? PSF component 15
424-445 E22.16 --- theta16 ? PSF component 16
447-468 E22.16 --- theta17 ? PSF component 17
470-492 E23.17 --- theta18 ? PSF component 18
494-515 E22.16 --- theta19 ? PSF component 19
517-535 F19.16 --- theta20 ? PSF component 20
537-555 F19.16 --- theta21 ? PSF component 21
557-579 E23.16 --- theta22 ? PSF component 22
581-599 E19.16 --- theta23 ? PSF component 23
601-619 F19.16 --- theta24 ? PSF component 24
621-639 F19.16 --- theta25 ? PSF component 25
641-662 E22.16 --- theta26 ? PSF component 26
664-682 F19.16 --- theta27 ? PSF component 27
--------------------------------------------------------------------------------
History:
From Hannu Parviainen, hannu(at)iac.es
Acknowledgements:
CHEOPS is a European Space Agency (ESA) mission in partnership with
Switzerland with important contributions to the payload and the ground
segment from Austria, Belgium, France, Germany, Hungary, Italy,
Portugal, Spain, Sweden and the United Kingdom.
(End) Patricia Vannier [CDS] 19-Apr-2023