J/A+A/672/A24 Geometric albedo of HD 189733b (Krenn+, 2023)
The geometric albedo of the hot Jupiter HD 189733b measured with CHEOPS.
Krenn A.F., Lendl M., Patel J.A., Carone L., Deleuil M., Sulis S.,
Collier Cameron A., Deline A., Guterman P., Queloz D., Fossati L.,
Brandeker A., Heng K., Akinsanmi B., Adibekyan V., Bonfanti A.,
Demangeon O.D.S., Kitzmann D., Salmon S., Sousa S.G., Wilson T.G.,
Alibert Y., Alonso R., Anglada G., Barczy T., Barrado Navascues D.,
Barros S.C.C., Baumjohann W., Beck M., Beck T., Benz W., Billot N.,
Blecha L., Bonfils X., Borsato L., Broeg C., Cabrera J., Charnoz S.,
Corral van Damme C., Csizmadia Sz., Cubillos P.E., Davies M.B., Delrez L.,
Demory B.-O., Ehrenreich D., Erikson A., Farinato J., Fortier A.,
Fridlund M., Gandolfi D., Gillon M., Guedel 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., 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., 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., Venturini J., Walton N.A.
<Astron. Astrophys. 672, A24 (2023)>
=2023A&A...672A..24K 2023A&A...672A..24K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry
Keywords: techniques: photometric - planets and satellites: atmosphere -
planets and satellites: individual: HD 189733b
Abstract:
Measurements of the occultation of an exoplanet at visible wavelengths
allow the reflective properties of a planetary atmosphere to be
determined. The observed occultation depth can be translated into a
geometric albedo. This in turn aids in characterising the structure
and composition of an atmosphere by providing additional information
on the wavelength-dependent reflective qualities of the aerosols in
the atmosphere.
Our aim is to provide a precise measurement of the geometric albedo of
the gas giant HD 189733b by measuring the occultation depth in the
broad optical bandpass of CHEOPS (350-1100nm).
We analysed 13 observations of the occultation of HD 189733b performed
by CHEOPS utilising the Python package PyCHEOPS. The resulting
occultation depth is then used to infer the geometric albedo
accounting for the contribution of thermal emission from the planet.
We also aid the analysis by refining the transit parameters combining
observations made by the TESS and CHEOPS space telescopes.
We report the detection of an 24.7±4.5ppm occultation in the
CHEOPS observations. This occultation depth corresponds to a geometric
albedo of 0.076±0.016. Our measurement is consistent with models
assuming the atmosphere of the planet to be cloud-free at the
scattering level and absorption in the CHEOPS band to be dominated by
the resonant Na doublet. Taking into account previous optical-light
occultation observations obtained with the Hubble Space Telescope,
both measurements combined are consistent with a super-stellar Na
elemental abundance in the dayside atmosphere of HD 189733b. We
further constrain the planetary Bond albedo to between 0.013 and 0.42
at 3-sigma confidence.
Description:
We present CHEOPS photometry (raw and detrended) of HD 189733b
containing two transits and 13 occultations.
Further we present detrended TESS photometry of HD 189733b.
ch1.dat contains the raw CHEOPS photometric time series with
auxiliary detrending vectors.
ch2.dat contains the detrended CHEOPS light curve
te1.dat contains the detrended TESS light curve
Objects:
-----------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------
20 00 43.71 +22 42 39.0 HD 189733 = BD+22 3887
-----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
ch1.dat 91 12314 Raw CHEOPS photometric time series with
auxiliary detrending vectors
ch2.dat 34 9956 Detrended CHEOPS light curve
te1.dat 34 18322 Detrended TESS light curve
--------------------------------------------------------------------------------
See also:
J/A+A/619/A96 : HD189733 spectral variability (Kohl+, 2018)
Byte-by-byte Description of file: ch1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 16 F14.6 d Time Time of mid-exposure (BJD)
18- 25 F8.6 --- NFlux Normalised raw flux
27- 34 F8.6 --- e_NFlux 1-sigma uncertainty in nfluX
36- 43 F8.4 deg Roll Spacecraft roll angle
45- 52 F8.4 pix CenX x-centroid position
54- 61 F8.4 pix CenY y-centroid position
63- 71 F9.7 --- Bg Fraction of flux in aperture from background
73- 81 F9.7 --- Contam Fraction of flux in aperture from nearby stars
83- 91 F9.7 --- smear Fraction of flux in aperture from readout
trails
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ch2.dat te1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 16 F14.6 d Time Time of mid-exposure (BJD)
18- 25 F8.6 --- NFlux-det Normalised detrended flux
27- 34 F8.6 --- e_NFlux-det 1-sigma uncertainty in NFlux-det
--------------------------------------------------------------------------------
Acknowledgements:
Andreas F. Krenn, andreas.krenn(at)oeaw.ac.at
(End) Andreas Krenn [OEAW], Patricia Vannier [CDS] 27-Jan-2023