Stellar Coronae

Summary Table

Category	Progenitor	Type	Energy Mechanism	Emission Mechanism	Counterparts									References	Brief Comments
					LF Radio	HF Radio	Microwave	Terahertz	Optical/IR	X-rays	Gamma-rays	Gravitational Waves	Neutrinos
Void	Stellar Corona	Both	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1310.2419, http://adsabs.harvard.edu/abs/2015MNRAS.454.2183M	None

Definitions: LF Radio (3 MHz to 3 GHz); HF Radio (3 GHz to 30 GHz); Microwave (30 to 300 GHz)

Model Description

One of the last surviving theories for FRBs of Galactic origins was flare stars. The theory was seemed fitting because dwarf stars have been observed to produce bursts of coherent radiation on short timescales ($< 5$ ms) and have been observed within FRB fields. A cyclotron maser in the lower part of the stellar corona could produce a flare consistent with FRB observations; the large DM and pulse smearing could be attributed to the corona plasma. Free-free absorption that occurs in the corona, however, presents a problem: a radio signal from the lower corona with the required DM may be unobservable unless the corona is infeasibly extended or hot. Further, the plasma density required for the DM is arguably too high to produce the frequency dependence on the pulse arrival times observed for FRBs. In defence of the theory, observations by are given that show high flare temperatures capable of mitigating significant free-free absorption. Further, if frequency drifts occur in flares (as observed in), the measured dispersion relationship for FRBs may be possible. Doubt is then cast on the theory again when it is shown that the brightness temperature of FRBs could not escape plasma as dense as the DM demands.

Observational Constraints

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