The flare catalog and the flare activity in the Kepler mission. (arXiv:1903.01056v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Yang_H/0/1/0/all/0/1">Huiqin Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Jifeng Liu</a>
We present a flare catalog of the {it Kepler} mission using the long-cadence
data of Data Release 25. This catalog comprises 3420 flare stars and 162,262
flare events. A comparison shows that the flare catalogs of previous studies
are seriously polluted by various false positive signals and artifacts. The
incidence of flare stars rises with decreasing temperature, which accords with
the theoretical analysis. The flare frequency distributions (FFDs) from F-type
stars to M-type stars obey a power-law relation with $alpha sim 2$,
indicating that they have the same mechanism on generating flares. The
remarkable incidence and the deviation of FFDs on A-type flare stars imply that
they generate flares in a different way. The activity–rotation relation is
consistent with previous studies at low temperature band, whereas it becomes
dispersive with increasing temperature. Combined with the Gyrochronology, we
find that the mixing of stars of two different dynamos gives rise to the
dispersion. We thereby propose a scenario on understanding the
activity–rotation relation across the H-R diagram. Based on the scenario and
the correspondence of dynamo with regard to activity and rotation, we suggest a
new expression on the activity–rotation relation, in which the segmentation is
on the basis of the dynamo rather than the rotation period. The rotation
distribution of flare stars shows that about 70% of flare stars rotate faster
than 10 days and the rate approaches 95% at 30 days. Based on the incidence
and the rotation distribution of flare stars, we estimate that a superflare
with energy $sim 10^{34}$ erg occurs on the Sun at least once in 5500 years.
We present a flare catalog of the {it Kepler} mission using the long-cadence
data of Data Release 25. This catalog comprises 3420 flare stars and 162,262
flare events. A comparison shows that the flare catalogs of previous studies
are seriously polluted by various false positive signals and artifacts. The
incidence of flare stars rises with decreasing temperature, which accords with
the theoretical analysis. The flare frequency distributions (FFDs) from F-type
stars to M-type stars obey a power-law relation with $alpha sim 2$,
indicating that they have the same mechanism on generating flares. The
remarkable incidence and the deviation of FFDs on A-type flare stars imply that
they generate flares in a different way. The activity–rotation relation is
consistent with previous studies at low temperature band, whereas it becomes
dispersive with increasing temperature. Combined with the Gyrochronology, we
find that the mixing of stars of two different dynamos gives rise to the
dispersion. We thereby propose a scenario on understanding the
activity–rotation relation across the H-R diagram. Based on the scenario and
the correspondence of dynamo with regard to activity and rotation, we suggest a
new expression on the activity–rotation relation, in which the segmentation is
on the basis of the dynamo rather than the rotation period. The rotation
distribution of flare stars shows that about 70% of flare stars rotate faster
than 10 days and the rate approaches 95% at 30 days. Based on the incidence
and the rotation distribution of flare stars, we estimate that a superflare
with energy $sim 10^{34}$ erg occurs on the Sun at least once in 5500 years.
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