Detailed cool star flare morphology with CHEOPS and TESS
Artikel i vetenskaplig tidskrift, 2024

Context. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and ultraviolet emission, their study is particularly relevant to estimate the amount of high-energy irradiation onto the atmospheres of exoplanets, especially those in their stars’ habitable zone. Aims. We used the high-cadence, high-photometric capabilities of the CHEOPS and TESS space telescopes to study the detailed morphology of white-light flares occurring in a sample of 130 late-K and M stars, and compared our findings with results obtained at a lower cadence. Methods. We employed dedicated software for the reduction of 3 s cadence CHEOPS data, and adopted the 20 s cadence TESS data reduced by their official processing pipeline. We developed an algorithm to separate multi-peak flare profiles into their components, in order to contrast them to those of single-peak, classical flares. We also exploited this tool to estimate amplitudes and periodicities in a small sample of quasi-periodic pulsation (QPP) candidates. Results. Complex flares represent a significant percentage (≳30%) of the detected outburst events. Our findings suggest that high-impulse flares are more frequent than suspected from lower-cadence data, so that the most impactful flux levels that hit close-in exoplanets might be more time-limited than expected. We found significant differences in the duration distributions of single and complex flare components, but not in their peak luminosity. A statistical analysis of the flare parameter distributions provides marginal support for their description with a log-normal instead of a power-law function, leaving the door open to several flare formation scenarios. We tentatively confirmed previous results about QPPs in high-cadence photometry, report the possible detection of a pre-flare dip, and did not find hints of photometric variability due to an undetected flare background. Conclusions. The high-cadence study of stellar hosts might be crucial to evaluate the impact of their flares on close-in exoplanets, as their impulsive phase emission might otherwise be incorrectly estimated. Future telescopes such as PLATO and Ariel, thanks to their high-cadence capability, will help in this respect. As the details of flare profiles and of the shape of their parameter distributions are made more accessible by continuing to increase the instrument precision and time resolution, the models used to interpret them and their role in star-planet interactions might need to be updated constantly.

methods: data analysis

techniques: photometric

stars: activity

stars: flare

planetary systems

Författare

G. Bruno

Istituto nazionale di astrofisica (INAF)

I. Pagano

Istituto nazionale di astrofisica (INAF)

Gaetano Scandariato

Istituto nazionale di astrofisica (INAF)

H.-G. Florén

Stockholms universitet

A. Brandeker

Stockholms universitet

G. Olofsson

Stockholms universitet

P. Maxted

Keele University

A. Fortier

Universität Bern

S.G. Sousa

Universidade do Porto

S. Sulis

Laboratoire d'Astrophysique de Marseille

V. Van Grootel

Universite de Liège

Z. Garai

Eötvös Loránd University (ELTE)

Slovak Academy of Sciences

HUN-REN-ELTE Exoplanet Research Group

Boldog

Magyar Tudomanyos Akademia

HUN-REN-ELTE Exoplanet Research Group

Research Centre For Astronomy and Earth Sciences

L. Kriskovics

Research Centre For Astronomy and Earth Sciences

Magyar Tudomanyos Akademia

Gy M. Szabó

HUN-REN-ELTE Exoplanet Research Group

Eötvös Loránd University (ELTE)

D. Gandolfi

Universita degli Studi di Torino

Y. Alibert

Universität Bern

R. Alonso

Universidad de la Laguna

Instituto de Astrofísica de Canarias

T. Bárczy

Admatis

D. Barrado Navascues

European Space Astronomy Centre (ESAC)

S.C.C. Barros

Universidade do Porto

W. Baumjohann

Institut fur Weltraumforschung

M. Beck

Université de Genève

T. Beck

Universität Bern

W. Benz

Universität Bern

N. Billot

Université de Genève

L. Borsato

Istituto nazionale di astrofisica (INAF)

C. Broeg

Universität Bern

A. Collier Cameron

University of St Andrews

Szilard Csizmadia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

P. E. Cubillos

Istituto nazionale di astrofisica (INAF)

Institut fur Weltraumforschung

M. B. Davies

Lunds universitet

M. Deleuil

Laboratoire d'Astrophysique de Marseille

A. Deline

Université de Genève

L. Delrez

Universite de Liège

KU Leuven

O. Demangeon

Universidade do Porto

B.O. Demory

Universität Bern

D. Ehrenreich

Université de Genève

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Farinato

Istituto nazionale di astrofisica (INAF)

L. Fossati

Institut fur Weltraumforschung

Malcolm Fridlund

Universiteit Leiden

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

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

S. Hoyer

Laboratoire d'Astrophysique de Marseille

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

L. L. Kiss

Pázmány Péter sétány 1/A

Magyar Tudomanyos Akademia

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)

C. Mordasini

Universität Bern

Valerio Nascimbeni

Istituto nazionale di astrofisica (INAF)

R. Ottensamer

Universität Wien

Enric Palle

Instituto de Astrofísica de Canarias

Universidad de la Laguna

G. Peter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Giampaolo P. Piotto

Università di Padova

Istituto nazionale di astrofisica (INAF)

Don L. Pollacco

The University of Warwick

D. Queloz

Eidgenössische Technische Hochschule Zürich (ETH)

University of Cambridge

Roberto Ragazzoni

Istituto nazionale di astrofisica (INAF)

Università di Padova

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

F. Ratti

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Freie Universität Berlin

I. Ribas

Institut de Ciències de l'Espai (ICE) - CSIC

Institut d'Estudis Espacials de Catalunya (IEEC)

N. C. Santos

Universidade do Porto

M. Sarajlic

Keele University

D. Segransan

Université de Genève

A.E. Simon

Universität Bern

V. Singh

Istituto nazionale di astrofisica (INAF)

A. M.S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Stalport

Universite de Liège

Nicolas Thomas

Universität Bern

S. Udry

Université de Genève

B. Ulmer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Venturini

Université de Genève

E. Villaver

Universidad de la Laguna

Instituto de Astrofísica de Canarias

N. A. Walton

University of Cambridge

T.G. Wilson

The University of Warwick

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 686 A239

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/202348951

Mer information

Senast uppdaterat

2024-07-01