Flare stars

Example observations of flare stars

EG UMa is a star with a post–common envelope in pre–cataclysmic stage. The star consists of a DAZ3.9 white dwarf and a M–dwarf star. According to GCVS EG UMa has brightness in a V filter about 12.5 magnitudo.

Equatorial coordinates of the star (ICRS): α(2000): 12h 15m44.1s, δ(2000): 52° 31′ 1.37″

On 13th of April 2011 the "Pi of the Sky" automatic trigger located near Huelva, Spain has detected an outburst of this star. During a few minutes of the night the star's brightness increased almost two magnitudo and in five minutes returns to its usual brightness.

Images below are 100x100 pixels, 36″/pixel, North up. 10 s long exposures, with 2 s readout time:

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Our light curve copmposed from single frames (click at the picture to enlarge) and some of our data points:


Our data:
HJDDate UTTime UTmagnitude
2455665.47802011.04.1323:24:3011.31
2455665.47812011.04.1323:24:4310.89
2455665.47822011.04.1323:24:5510.84
2455665.47842011.04.1323:25:0810.93
2455665.47852011.04.1323:25:2110.96
2455665.47872011.04.1323:25:3311.13
2455665.47882011.04.1323:25:4611.13
2455665.47902011.04.1323:25:5911.40
2455665.47912011.04.1323:26:1111.46
2455665.47922011.04.1323:26:2411.24
2455665.47942011.04.1323:26:3711.54
2455665.47952011.04.1323:26:5011.28
2455665.47972011.04.1323:27:0211.20
2455665.47982011.04.1323:27:1511.69
2455665.48002011.04.1323:27:2811.65
2455665.48032011.04.1323:27:5311.56
2455665.48042011.04.1323:28:0611.74
2455665.48062011.04.1323:28:1911.89
2455665.48092011.04.1323:28:4412.00