No random transits in CHEOPS observations of HD 139139*,**
Artikel i vetenskaplig tidskrift, 2023
Context. The star HD 139139 (a.k.a. ‘the Random Transiter’) is a star that exhibited enigmatic transit-like features with no apparent periodicity in K2 data. The shallow depth of the events (-200 ppm - equivalent to transiting objects with radii of -1.5 R⊕ in front of a Sun-like star) and their non-periodicity constitute a challenge for the photometric follow-up of this star. Aims. The goal of this study is to confirm with independent measurements the presence of shallow, non-periodic transit-like features on this object.
Methods. We performed observations with CHEOPS for a total accumulated time of 12.75 days, distributed in visits of roughly 20 h in two observing campaigns in years 2021 and 2022. The precision of the data is sufficient to detect 150 ppm features with durations longer than 1.5 h. We used the duration and times of the events seen in the K2 curve to estimate how many events should have been detected in our campaigns, under the assumption that their behaviour during the CHEOPS observations would be the same as in the K2 data of 2017.
Results. We do not detect events with depths larger than 150 ppm in our data set. If the frequency, depth, and duration of the events were the same as in the K2 campaign, we estimate the probability of having missed all events due to our limited observing window would be 4.8%.
Conclusions. We suggest three different scenarios to explain our results: 1) Our observing window was not long enough, and the events were missed with the estimated 4.8% probability. 2) The events recorded in the K2 observations were time critical, and the mechanism producing them was either not active in the 2021 and 2022 campaigns or created shallower events under our detectability level. 3) The enigmatic events in the K2 data are the result of an unidentified and infrequent instrumental noise in the original data set or its data treatment.
Methods. We performed observations with CHEOPS for a total accumulated time of 12.75 days, distributed in visits of roughly 20 h in two observing campaigns in years 2021 and 2022. The precision of the data is sufficient to detect 150 ppm features with durations longer than 1.5 h. We used the duration and times of the events seen in the K2 curve to estimate how many events should have been detected in our campaigns, under the assumption that their behaviour during the CHEOPS observations would be the same as in the K2 data of 2017.
Results. We do not detect events with depths larger than 150 ppm in our data set. If the frequency, depth, and duration of the events were the same as in the K2 campaign, we estimate the probability of having missed all events due to our limited observing window would be 4.8%.
Conclusions. We suggest three different scenarios to explain our results: 1) Our observing window was not long enough, and the events were missed with the estimated 4.8% probability. 2) The events recorded in the K2 observations were time critical, and the mechanism producing them was either not active in the 2021 and 2022 campaigns or created shallower events under our detectability level. 3) The enigmatic events in the K2 data are the result of an unidentified and infrequent instrumental noise in the original data set or its data treatment.
stars
peculiar - planets and satellites
photometric
detection - techniques
Författare
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
S. Hoyer
Laboratoire d'Astrophysique de Marseille
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A.E. Simon
Universität Bern
M. Beck
Université de Genève
W. Benz
Universität Bern
H.-G. Florén
Stockholms universitet
P. Guterman
CS20330
Laboratoire d'Astrophysique de Marseille
L. Borsato
Istituto nazionale di astrofisica (INAF)
A. Brandeker
Stockholms universitet
D. Gandolfi
Universita degli Studi di Torino
T.G. Wilson
University of St Andrews
Tiziano Zingales
Università di Padova
Istituto nazionale di astrofisica (INAF)
Y. Alibert
Universität Bern
G. Anglada
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
T. Bárczy
Admatis
D. Barrado Navascues
European Space Astronomy Centre (ESAC)
S.C.C. Barros
Universidade do Porto
W. Baumjohann
Institut fur Weltraumforschung
T. Beck
Universität Bern
N. Billot
Université de Genève
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
C. Broeg
Universität Bern
S. Charnoz
Institut de Physique du Globe de Paris
A. Collier Cameron
University of St Andrews
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
P. E. Cubillos
Institut fur Weltraumforschung
Istituto nazionale di astrofisica (INAF)
M.B. Davies
Lunds universitet
A. Deline
Université de Genève
L. Delrez
Universite de Liège
O. Demangeon
Universidade do Porto
B.O. Demory
Universität Bern
D. Ehrenreich
Université de Genève
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Universität Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Universiteit Leiden
Michaël Gillon
Universite de Liège
M. Gudel
Universität Wien
Maximilian N. Günther
European Space Research and Technology Centre (ESA ESTEC)
A. Heitzmann
Université de Genève
Ch. Helling
Institut fur Weltraumforschung
Technische Universität Graz
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. Kiss
Magyar Tudomanyos Akademia
Eötvös Loránd University (ELTE)
E. Kopp
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
K. W.F. Lam
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Observatoire de Paris
A. L. des Etangs
Institut d 'Astrophysique de Paris
M. Lendl
Université de Genève
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
C. Mordasini
Universität Bern
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
I. Pagano
Istituto nazionale di astrofisica (INAF)
Enric Palle
Instituto de Astrofísica de Canarias
Universidad de la Laguna
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
Università di Padova
Don L. Pollacco
The University of Warwick
D. Queloz
University of Cambridge
Eidgenössische Technische Hochschule Zürich (ETH)
R. Ragazzoni
Istituto nazionale di astrofisica (INAF)
Università di Padova
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Technische Universität Berlin
Freie Universität Berlin
I. Ribas
Institut d'Estudis Espacials de Catalunya (IEEC)
Institut de Ciències de l'Espai (ICE) - CSIC
N. C. Santos
Universidade do Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
Université de Genève
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S.G. Sousa
Universidade do Porto
M. Stalport
Universite de Liège
G.M. Szabó
HUN-REN-ELTE Exoplanet Research Group
Eötvös Loránd University (ELTE)
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
B. Ulmer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
V. Van Grootel
Universite de Liège
J. Venturini
Université de Genève
F. Verrecchia
Osservatorio Astronomico di Roma
Agenzia Spaziale Italiana
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 680 A78Ämneskategorier
Astronomi, astrofysik och kosmologi
Sannolikhetsteori och statistik
DOI
10.1051/0004-6361/202347779