Observational signs of limited flare area variation and peak flare temperature estimations in main-sequence flaring stars

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00637342" target="_blank" >RIV/67985815:_____/25:00637342 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0368248" target="_blank" >https://hdl.handle.net/11104/0368248</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202452867" target="_blank" >10.1051/0004-6361/202452867</a>

Result language

angličtina

Original language name

Observational signs of limited flare area variation and peak flare temperature estimations in main-sequence flaring stars

Original language description

In the study of stellar flares, traditional method of calculating total energy emitted in the continuum assumes the emission originating from a narrow chromospheric condensation region with a constant temperature of 10 000 K and variable flare area. However, based on multicolor data from seven new flares observed in Białków and Shumen observatory and eight previously published flares observed on ten main-sequence stars (spectral types M5.5V to K5V nine M-dwarfs and one K-dwarf) we show that flare areas had a relative change in the range of 10-61% (for more than half of the flares this value did not exceed 30%) throughout the events except for the impulsive phase, and had values starting from 50 +/- 30 ppm to 300 +/- 150 ppm for our new flares and from 380 +/- 200 ppm to 7600 +/- 3000 ppm from previously published flare data, while their temperature increased on average by the factor 2.5. The peak flare temperatures for our seven observed flares ranged from 5700 +/- 450 K to 17 500 +/- 10 050 K. Five of these flares had their temperatures estimated using the Johnson-Kron-Cousins B filter alongside TESS (Transiting Exoplanet Survey Satellite) data, one flare was analyzed using the SLOAN g ' and r ' bandpasses, and another was evaluated using both the SLOAN g ' and r ' bandpasses and TESS data. Using flare temperature and area data, along with the physical parameters of stars where the flares occurred, we developed a semiempirical grid that correlates a star's effective temperature and flare amplitude in TESS data with the flare's peak temperature. This allows interpolation of a flare's peak temperature based on the star's effective temperature (ranging from 2700 K to 4600 K) and flare amplitude from TESS observations. Applying this grid to 42 257 flares from TESS survey, we estimated peak flare temperatures between 5700 K and 38 300 K, with most flares showing peak blackbody temperatures around 11 100 +/- 2400 K.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GF22-30516K" target="_blank" >GF22-30516K: Superflares: Their origins and connection with planets</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

699

Issue of the periodical within the volume

July

Country of publishing house

FR - FRANCE

Number of pages

13

Pages from-to

A90

UT code for WoS article

001521303900020

EID of the result in the Scopus database

2-s2.0-105009789313