J/MNRAS/514/77 CHEOPS Early Science observations (Maxted+, 2022)
Analysis of Early Science observations with the CHaracterising
ExOPlanets Satellite (CHEOPS) using PYCHEOPS.
Maxted P.F.L., Ehrenreich D., Wilson T.G., Alibert Y., Collier Cameron A.,
Hoyer S., Sousa S.G., Olofsson G., Bekkelien A., Delrez L., Bonfanti A.,
Borsato L., 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., Brandeker A., Broeg C., Cabrera J., Charnoz S., Csizmadia Sz.,
Davies M.B., Deleuil M., Deline A., Demangeon O.D.S., Demory B.-O.,
Erikson A., Floren H.G., Fortier A., Fossati L., Fridlund M., Futyan D.,
Gandolfi D., Gillon M., Guedel M., Guterman P., Heng K., Isaak K.G.,
Kiss L., Laskar J., Lecavelier des Etangs A., Lendl M., Lovis C.,
Magrin D., Nascimbeni V., Ottensamer R., Pagano I., Palle E., Peter G.,
Piotto G., Pollacco D., Pozuelos F.J., Queloz D., Ragazzoni R., Rando N.,
Rauer H., Reimers C., Ribas I., Salmon S., Santos N.C., Scandariato G.,
Segransan D., Simon A.E., Smith A.M.S., Steller M., Szabo Gy.M., Thomas N.,
Udry S., Van Grootel V., Walton N.A.
<Mon. Not. R. Astron. Soc. 514, 77-104 (2022)>
=2022MNRAS.514...77M 2022MNRAS.514...77M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Photometry
Mission_Name: CHEOPS
Keywords: methods: data analysis - software: data analysis -
planets and satellites: fundamental parameters
Abstract:
CHEOPS (CHaracterising ExOPlanet Satellite) is an ESA S-class mission
that observes bright stars at high cadence from low-Earth orbit. The
main aim of the mission is to characterize exoplanets that transit
nearby stars using ultrahigh precision photometry. Here we report the
analysis of transits observed by CHEOPS during its Early Science
observing programme for four well- known exoplanets: GJ 436 b,
HD 106315 b, HD 97658 b and GJ 1132 b. The analysis is done using
pycheops, an open-source software package we have developed to easily
and efficiently analyse CHEOPS light curve data using state-of-the-art
techniques that are fully described herein. We show that the precision
of the transit parameters measured using CHEOPS is comparable to that
from larger space telescopes such as Spitzer Space Telescope and
Kepler. We use the updated planet parameters from our analysis to
derive new constraints on the internal structure of these four
exoplanets.
Description:
CHEOPS photometry of GJ 436, HD 106315, HD 97658 and GJ 1132 generated
using pycheops version 1.0.0.
Objects:
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RA (2000) DE Designation(s)
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11 42 11.09 +26 42 23.7 GJ 436 = TIC 138819293
12 13 53.40 -00 23 36.6 HD 106315 = K2-109
10 14 51.78 -47 09 24.2 GJ 1132 = TIC 101955023
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 9 Log of CHEOPS observations
lc01.dat 108 272 Dataset CHPR100041TG000302_V0102, GJ 436
lc02.dat 108 269 Dataset CHPR100041TG000303_V0102, GJ 436
lc03.dat 108 228 Dataset CHPR100041TG001301_V0102, GJ 436
lc04.dat 108 1813 Dataset CHPR100041TG000802_V0102, HD 106315
lc05.dat 108 1037 Dataset CHPR100041TG001401_V0102, HD 106315
lc06.dat 108 485 Dataset CHPR100041TG001201_V0102, HD 97658
lc07.dat 108 255 Dataset CHPR100041TG000401_V0102, GJ 1132
lc08.dat 108 208 Dataset CHPR100041TG000402_V0102, GJ 1132
lc09.dat 108 253 Dataset CHPR100041TG000403_V0102, GJ 1132
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- N [1/3] Sequence number
3- 11 A9 --- Target Star name
13- 17 F5.2 mag Gmag Gaia G magnitude
19- 37 A19 "datime" Start Stat date
39- 43 I5 s Dur Duration
45- 48 A4 s Texp Exposure time in terms of the integration time
per image multiplied by the number of images
stacked on-board prior to download (NxNN)
50- 53 I4 --- Nobs Number of observations
55- 56 I2 % Eff Fraction of the observing interval covered by
valid observations of the target
58- 84 A27 --- Filekey File key
85- 88 F4.1 pix Rap Aperture radius used to compute the light
curve analysed in this paper
90- 97 A8 --- FileName Name of the table with light curve data
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Byte-by-byte Description of file: lc*.dat
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Bytes Format Units Label Explanations
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1- 16 F16.6 d Time Time of mid-exposure
18- 25 F8.6 --- Flux Normalized flux
27- 34 F8.6 --- e_Flux Normalized flux error
36- 43 F8.6 --- Fluxd Normalized flux corrected for instrumental trends
45- 52 F8.4 pix xoff Target position offset in x-direction
54- 61 F8.4 pix yoff Target position offset in y-direction
63- 70 F8.4 deg roll Spacecraft roll angle
72- 80 F9.7 --- contam Fraction of flux in aperture from nearby stars
82- 90 F9.7 --- smear Fraction of flux in aperture from readout trails
92-100 F9.7 --- bg Fraction of flux in aperture from background
102-108 F7.3 --- Temp2 Temperature sensor reading
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Acknowledgements:
Pierre Maxted, p.maxted(at)keele.ac.uk
(End) Patricia Vannier [CDS] 20-May-2022