Open AccessOptical flares and flaring oscillations on the M‐type eclipsing binary CU Cancri
Author(s) -
Qian S.B.,
Zhang J.,
Zhu L.Y.,
Liu L.,
Liao W.P.,
Zhao E.G.,
He J.J.,
Li L.J.,
Li K.,
Dai Z.B.
Publication year - 2012
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2012.21157.x
Subject(s) - physics , astrophysics , flare , flare star , astronomy , solar flare , stars , brown dwarf , light curve , k type main sequence star , t tauri star
In this paper, we report on the discovery of an optical flare observed in the R band from the red‐dwarf eclipsing binary CU Cancri, whose component stars are at the upper boundary of full convection ( M 1 = 0.43 M ⊙ and M 2 = 0.4 M ⊙ , where M ⊙ is the solar mass). The amplitude of the flare is the largest among those detected in the R band (∼0.52 mag) and the duration time is about 73 min. Like flares observed on the Sun, quasi‐periodic oscillations were seen during and after the flare. Three more R ‐band flares were found by follow‐up monitoring. In total, this binary was monitored photometrically by using an R filter for 79.9 h, which has revealed an R ‐band flare rate of about 0.05 flares per hour. Together with other strong chromospheric and coronal activities (i.e. very strong H α and H β emission features and an extreme ultraviolet and X‐ray source), these detections indicate that it has very strong magnetic activity. Therefore, the apparent faintness (∼1.4 mag in the V band) of CU Cnc, compared with other single red dwarfs of the same mass, can be plausibly explained by the high coverage of dark spots.