Abstract Stellar flares are short-duration (< hours) bursts of radiation associated with surface magnetic reconnection events. Stellar magnetic activity generally decreases as a function of both the age and Rossby number,R0, a measure of the relative importance of the convective and rotational dynamos. Young stars (<300 Myr) have typically been overlooked in population-level flare studies due to challenges with flare-detection methods. Here, we select a sample of stars that are members of 26 nearby moving groups, clusters, or associations with ages <300 Myr that have been observed by the Transiting Exoplanet Survey Satellite at 2 minute cadence. We identified 26,355 flares originating from 3160 stars and robustly measured the rotation periods of 1847 stars. We measure and find the flare frequency distribution slope,α, saturates for all spectral types atα∼ −0.5 and is constant over 300 Myr. Additionally, we find that flare rates for starstage= 50–250 Myr are saturated belowR0< 0.14, which is consistent with other indicators of magnetic activity. We find evidence of annual flare rate variability in eleven stars, potentially correlated with long-term stellar activity cycles. Additionally, we crossmatch our entire sample with the Galaxy Evolution Explorer and find no correlation between flare rate and far- and near-ultraviolet flux. Finally, we find the flare rates of planet-hosting stars are relatively lower than comparable, larger samples of stars, which may have ramifications for the atmospheric evolution of short-period exoplanets.
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Llamaradas Estelares: Modeling the Morphology of White-light Flares
Abstract Stellar variability is a limiting factor for planet detection and characterization, particularly around active M-type stars. Here we revisit one of the most active stars from the Kepler mission, the M4 star GJ 1243, and use a sample of 414 flare events from 11 months of 1-minute cadence light curves to study the empirical morphology of white-light stellar flares. We use a Gaussian process detrending technique to account for the underlying starspots. We present an improved analytic, continuous flare template that is generated by stacking the flares onto a scaled time and amplitude and uses a Markov Chain Monte Carlo analysis to fit the model. Our model is defined using classical flare events but can also be used to model complex, multipeaked flare events. We demonstrate the utility of our model using TESS data at the 10-minute, 2-minute, and 20 s cadence modes. Our new flare model code is made publicly available on GitHub. 5 5 https://github.com/lupitatovar/Llamaradas-Estelares
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- Award ID(s):
- 1907342
- PAR ID:
- 10353630
- Date Published:
- Journal Name:
- The Astronomical Journal
- Volume:
- 164
- Issue:
- 1
- ISSN:
- 0004-6256
- Page Range / eLocation ID:
- 17
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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