59128
doi
10.5281/zenodo.59128
oai:zenodo.org:59128
user-cs19
An Optical Megaflare on EV Lac
Pettersen, B. R.
University of Oslo
info:eu-repo/semantics/openAccess
Creative Commons Zero v1.0 Universal
https://creativecommons.org/publicdomain/zero/1.0/legalcode
flare star
photometry
EV Lac
<p>We present a U-filter light curve of a very intensive flare on EV Lac, observed at 1 s time resolution with a 2 m telescope at BNAO. The monitoring lasted for 7.4 hours (UT 16:40-UT 24:04) on 01 November 1991, and EV Lac was affected by flaring throughout this time. The data have been corrected for atmospheric extinction and the presence of an optical companion in the photometer diaphragm.</p>
<p>A ΔU=7.2 magnitude flare maximum (L<sub>f,U</sub> = 4.6 · 10<sup>31</sup> ergs s<sup>-1</sup>) represents an increase of 735 times the flux of the quiescent star. This is twice as large as a flare reported by Roizman and Shevchenko (1982, Sov. Astron. Lett. <strong>8, </strong>85-86) and is 88% of the bolometric luminosity of EV Lac. The eruptive phase of the rise took 72 seconds, and the flare returned to half its maximum value in t<sub>0.5</sub> = 39 seconds. The classically peak-shaped flare went into a slow decay phase after about 20 minutes. Several secondary flares were superposed on the > 5 hours decay. The U-filter flare energy released during the major peak was 7.23 · 10<sup>33</sup> ergs. It accounts for 93% of the energy released during the entire flare event (E<sub>U</sub> = 7.8 · 10<sup>33</sup> ergs). </p>
<p>The flare occurred close to maximum brightness of the 4.4 days rotational modulation of EV Lac, which had a V-amplitude 0.06 mag in 1991.</p>
Zenodo
2016-06-26
info:eu-repo/semantics/conferencePaper
639533
user-cs19
1579528395.336588
600673
md5:6ff57ee57424dc4f37caa9f779955ae4
https://zenodo.org/records/59128/files/Text.pdf
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