J/A+A/664/L15 Quaoar's stellar occultation observed by CHEOPS (Morgado+, 2022)
A stellar occultation by the transneptunian object (50000) Quaoar observed
by CHEOPS.
Morgado B.E., Bruno G., Gomes-Junior A.R., Pagano I., Sicardy B.,
Fortier A., Desmars J., Maxted P.F.L., Braga-Ribas F., Queloz D.,
Sousa S.G., Ortiz J.L., Brandeker A., Collier Cameron A., Pereira C.L.,
Floren H.G., Hara N., Souami D., Isaak K.G., Olofsson G., Santos-Sanz P.,
Wilson T.G., Broughton J., Alibert Y., Alonso R., Anglada G., Barczy T.,
Barrado D., Barros S.C.C., Baumjohann W., Beck M., Beck T., Benz W.,
Billot N., Bonfils X., Broeg C., Cabrera J., Charnoz S., Csizmadia S.,
Davies M.B., Deleuil M., Delrez L., Demangeon O.D.S., Demory B.O.,
Ehrenreich D., Erikson A., Fossati L., Fridlund M., Gandolfi D., Gillon M.,
Guedel M., Heng K., Hoyer S., Kiss L.L., Laskar J.,
Lecavelier des Etangs A., Lendl M., Lovis C., Magrin D., Marafatto L.,
Nascimbeni V., Ottensamer R., Palle E., Peter G., Piazza D., Piotto G.,
Pollacco D., Ragazzoni R., Rando N., Ratti F., Rauer H., Reimers C.,
Ribas I., Santos N.C., 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., Westerdorff K.
<Astron. Astrophys. 664, L15 (2022)>
=2022A&A...664L..15M 2022A&A...664L..15M (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Occultations
Keywords: methods: observational - techniques: photometry - occultations -
minor planets, asteroids: individual: Quaoar
Abstract:
Stellar occultation is a powerful technique that allows the
determination of some physical parameters of the occulting object. The
result depends on the photometric accuracy, the temporal resolution,
and the number of chords obtained. Space telescopes can achieve high
photometric accuracy as they are not affected by atmospheric
scintillation. Using ESA's CHEOPS space telescope, we observed a
stellar occultation by the Transneptunian object (50000) Quaoar. We
compare the obtained chord with previous occultations by this object
and determine its astrometry with sub-milliarcsecond precision. Also,
we determine upper limits to the presence of a global methane
atmosphere on the occulting body. We predicted and observed a stellar
occultation by Quaoar using the CHEOPS space telescope. We measured
the occultation light curve from this data-set and determined the dis-
and re-appearance of the star behind the occulting body. Furthermore,
a ground-based telescope in Australia was used to constrain Quaoar's
limb. Combined with results from previous works, these measurements
allow us to obtain a precise position of Quaoar at the occultation
time. We present results obtained from the first stellar occultation
by a Transneptunian object (TNO) using space telescope orbiting Earth.
It was the occultation by Quaoar observed on 2020 June 11. We used the
CHEOPS light curve to obtain a surface pressure upper limit of 85 nbar
for the detection of a global methane atmosphere. Also, combining this
observation with a ground-based observation we fit Quaoar's limb to
determine its astrometric position with an uncertainty below 1.0 mas.
This observation is a first of its kind, and it shall be considered as
a proof of concept of stellar occultation observations of
Transneptunian objects with space telescopes orbiting Earth. Moreover,
it shows significant prospects for the James Webb Space Telescope.
Description:
Light flux of the occulted star plus the occulting object during the
stellar occultation for each observer, also the best fitted model and
their residuals.
objects:
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Planet Name H i e a
mag deg AU
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50000 Quaoar 2.51 7.990425 0.04154574 43.64120180
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lc_broug.dat 67 1194 Light curve containing J. Broughton observation
lc_cheop.dat 67 1148 Light curve containing CHEOPS observation
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Byte-by-byte Description of file: lc_broug.dat lc_cheop.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d JD Julian date of mid-exposure observation
18- 31 F14.8 s Time Seconds relative to 2020-06-11 15:45:00.000 UTC
34- 43 F10.8 --- Fobs Normalised observed flux
46- 55 F10.8 --- Ffit Normalised best fitted modelled flux
57- 67 F11.8 --- res Residual O-C
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History:
From Bruno Morgado, morgado.fis(at)gmail.com
Acknowledgements:
This work was carried out within the "Lucky Star" umbrella that
agglomerates the efforts of the Paris, Granada and Rio teams, which is
funded by the European Research Council under the European
Community's H2020 (ERC Grant Agreement No. 669416). CHEOPS is an 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. The CHEOPS Consortium would like to gratefully acknowledge
the support received by all the agencies, offices, universities, and
industries involved. Their flexibility and willingness to explore new
approaches were essential to the success of this mission. This
research made use of sora, a python package for stellar occultations
reduction and analysis, developed with the support of ERC Lucky Star
and LIneA/Brazil, within the collaboration of Rio-Paris-Granada teams.
This work has made use of data from the European Space Agency (ESA)
mission Gaia (https://www.cosmos.esa.int/gaia), processed by the
Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). This study was
financed in part by the National Institute of Science and Technology
of the e-Universe project (INCT do e-Universo, CNPq grant
465376/2014-2). The following authors acknowledge the respective i)
CNPq grants: BEM 150612/2020-6; FB-R 314772/2020-0; ii) CAPES/Cofecub
grant: BEM 394/2016-05. ii) FAPESP grants: ARGJr 2018/11239-8; GBr,
VNa, IPa, GPi, RRa, and GSc acknowledge support from CHEOPS ASI-INAF
agreement n. 2019-29-HH.0.
ABr was supported by the SNSA. RCA programme. The MOC activities have
been supported by the ESA contract No. 4000124370.
S.C.C.B. acknowledges support from FCT through FCT contracts nr.
IF/01312/2014/CP1215/CT0004. XB, SC, DG, MF and JL acknowledge their
role as ESA-appointed CHEOPS science team members. This project was
supported by the CNES.
The Belgian participation to CHEOPS has been supported by the Belgian
Federal Science Policy Office (BELSPO) in the framework of the PRODEX
Program, and by the University of Liege through an ARC grant for
Concerted Research Actions financed by the Wallonia-Brussels
Federation. L.D. is an F.R.S.-FNRS Postdoctoral Researcher.
This work was supported by FCT - Fundacao para a Ciencia e a
Tecnologia through national funds and by FEDER through COMPETE2020 -
Programa Operacional Competitividade e Internacionalizacao by these
grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020,
PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER- 032113,
PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953,
PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O.D.S.D. is
supported in the form of work contract (DL 57/2016/CP1364/CT0004)
funded by national funds through FCT.
P.S-S. acknowledges financial support by the Spanish grant
AYA-RTI2018-098657-J-I00 "LEO-SBNAF" (MCIU/AEI/FEDER, UE). P.S-S.
and J.L.O. acknowledge financial support from the State Agency for
Research of the Spanish MCIU through the "Center of Excellence
Severo Ochoa" award for the Instituto de Astrofisica de Andalucia
(SEV-2017-0709), they also acknowledge the financial support by the
Spanish grants AYA-2017-84637-R and PID2020-112789GB-I00, and the
Proyectos de Excelencia de la Junta de Andalucia 2012-FQM1776 and
PY20-01309. B.-O.D. acknowledges support from the Swiss National
Science Foundation (PP00P2-190080). This project has received funding
from the European Research Council (ERC) under the European Union's
Horizon 2020 research and innovation programme (project Four Aces).
grant agreement No 724427). It has also been carried out in the frame
of the National Centre for Competence in Research PlanetS supported by
the Swiss National Science Foundation (SNSF). DE acknowledges
financial support from the Swiss National Science Foundation for
project 200021_200726.
MF and CMP gratefully acknowledge the support of the Swedish National
Space Agency (DNR 65/19, 174/18). DG gratefully acknowledges financial
support from the CRT foundation under Grant No. 2018.2323 ``Gaseous or
rocky? Unveiling the nature of small worlds''. M.G. is an F.R.S.-FNRS
Senior Research Associate. SH gratefully acknowledges CNES funding
through the grant 837319. This work was granted access to the HPC
resources of MesoPSL financed by the Region Ile de France and the
project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme
Investissements d'Avenir supervised by the Agence Nationale pour la
Recherche. ML acknowledges support of the Swiss National Science
Foundation under grant number PCEFP2_194576. PM acknowledges support
from STFC research grant number ST/M001040/1. This work was also
partially supported by a grant from the Simons Foundation (PI Queloz,
grant number 327127). IRI acknowledges support from the Spanish
Ministry of Science and Innovation and the European Regional
Development Fund through grant PGC2018-098153-B- C33, as well as the
support of the Generalitat de Catalunya/CERCA programme. S.G.S.
acknowledge support from FCT through FCT contract nr.
CEECIND/00826/2018 and POPH/FSE (EC). GyMSz acknowledges the support
of the Hungarian National Research, Development and Innovation Office
(NKFIH) grant K-125015, a a PRODEX Experiment Agreement No.
4000137122, the Lendulet LP2018-7/2021 grant of the Hungarian
Academy of Science and the support of the city of Szombathely.
VVG. is an F.R.S-FNRS Research Associate.
NAW acknowledges UKSA grant ST/R004838/1.
(End) Patricia Vannier [CDS] 10-Aug-2022