CHEOPS precision phase curve of the Super-Earth 55 Cancri e
Journal article, 2021
Context. 55 Cnc e is a transiting super-Earth (radius 1.88 R-circle plus and mass 8 M-circle plus) orbiting a G8V host star on a 17-h orbit. Spitzer observations of the planet's phase curve at 4.5 mu m revealed a time-varying occultation depth, and MOST optical observations are consistent with a time-varying phase curve amplitude and phase offset of maximum light. Both broadband and high-resolution spectroscopic analyses are consistent with either a high mean molecular weight atmosphere or no atmosphere for planet e. A long-term photometric monitoring campaign on an independent optical telescope is needed to probe the variability in this system. Aims. We seek to measure the phase variations of 55 Cnc e with a broadband optical filter with the 30 cm effective aperture space telescope CHEOPS and explore how the precision photometry narrows down the range of possible scenarios. Methods. We observed 55 Cnc for 1.6 orbital phases in March of 2020. We designed a phase curve detrending toolkit for CHEOPS photometry which allowed us to study the underlying flux variations in the 55 Cnc system. Results. We detected a phase variation with a full-amplitude of 72 +/- 7 ppm, but did not detect a significant secondary eclipse of the planet. The shape of the phase variation resembles that of a piecewise-Lambertian; however, the non-detection of the planetary secondary eclipse, and the large amplitude of the variations exclude reflection from the planetary surface as a possible origin of the observed phase variations. They are also likely incompatible with magnetospheric interactions between the star and planet, but may imply that circumplanetary or circumstellar material modulate the flux of the system. Conclusions. This year, further precision photometry of 55 Cnc from CHEOPS will measure variations in the phase curve amplitude and shape over time.
planets and satellites: individual: 55 Cnc e
planets and satellites: atmospheres
techniques: photometric
instrumentation: photometers
stars: individual: 55 Cnc
methods: observational
Author
B. M. Morris
University of Bern
L. Delrez
University of Geneva
University of Liège
A. Brandeker
Stockholm University
A. C. Cameron
University of St Andrews
A. E. Simon
University of Bern
D. Futyan
University of Geneva
G. Olofsson
Stockholm University
S. Hoyer
Aix Marseille University
A. Fortier
University of Bern
B-O Demory
University of Bern
M. Lendl
University of Geneva
T. G. Wilson
University of St Andrews
M. Oshagh
Instituto de Astrofísica de Canarias
University of La Laguna
K. Heng
University of Bern
D. Ehrenreich
University of Geneva
S. Sulis
Aix Marseille University
Y. Alibert
University of Bern
R. Alonso
University of La Laguna
Instituto de Astrofísica de Canarias
G. Anglada Escude
Spanish National Research Council (CSIC)
Institute of Space Studies of Catalonia (IEEC)
D. Barrado
Spanish Astrobiology Center (INTA-CSIC)
S. C. C. Barros
University of Porto
W. Baumjohann
Austrian Academy of Sciences
M. Beck
University of Geneva
T. Beck
University of Bern
A. Bekkelien
University of Geneva
W. Benz
University of Bern
M. Bergomi
Istituto nazionale di astrofisica (INAF)
N. Billot
University of Geneva
X. Bonfils
Grenoble Alpes University
V Bourrier
University of Geneva
C. Broeg
University of Bern
T. Barczy
Admatis
J. Cabrera
German Aerospace Center (DLR)
S. Charnoz
Paris Descartes University
M. B. Davies
Lund University
D. De Miguel Ferreras
Airbus Group
M. Deleuil
Aix Marseille University
A. Deline
University of Geneva
O. D. S. Demangeon
University of Porto
A. Erikson
German Aerospace Center (DLR)
H. G. Floren
Stockholm University
L. Fossati
Austrian Academy of Sciences
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
D. Gandolfi
University of Turin
A. Garcia Munoz
Technische Universität Berlin
M. Gillon
University of Liège
M. Guedel
University of Vienna
P. Guterman
Institut National des Sciences de l'Univers
Aix Marseille University
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. Kiss
The University of Sydney
Eötvös Loránd University (ELTE)
Hungarian Academy of Sciences
J. Laskar
Université Paris PSL
A. Lecavelier des Etangs
Pierre and Marie Curie University (UPMC)
M. Lieder
German Aerospace Center (DLR)
C. Lovis
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. F. L. Maxted
Keele University
V Nascimbeni
Istituto nazionale di astrofisica (INAF)
R. Ottensamer
University of Vienna
I Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
University of La Laguna
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
G. Piotto
University of Padua
Istituto nazionale di astrofisica (INAF)
A. Pizarro Rubio
Airbus Group
D. Pollacco
The University of Warwick
F. J. Pozuelos
University of Liège
D. Queloz
University of Cambridge
University of Geneva
R. Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Agency (ESA)
H. Rauer
Technische Universität Berlin
German Aerospace Center (DLR)
Freie Universität Berlin
I Ribas
Institute of Space Studies of Catalonia (IEEC)
Spanish National Research Council (CSIC)
N. C. Santos
University of Porto
G. Scandariato
Istituto nazionale di astrofisica (INAF)
A. M. S. Smith
German Aerospace Center (DLR)
S. G. Sousa
University of Porto
M. Steller
Austrian Academy of Sciences
Gy M. Szabo
Eötvös Loránd University (ELTE)
D. Segransan
University of Geneva
N. Thomas
University of Bern
S. Udry
University of Geneva
B. Ulmer
Ingenieurbüro Ulmer
V. Van Grootel
University of Liège
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 653 A173Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Other Physics Topics
DOI
10.1051/0004-6361/202140892