Observations of X-ray flares on π¹ UMa

Abstract

We investigate the properties of the quiescent and flaring coronae of an active solar-type star π¹ UMa using XMM–Newton observation. The present data show that the quiescent state coronae of π¹ UMa consist of two temperatures 4.7 and 7.9 MK and it has an X-ray luminosity of 7.4 × 10²⁸ erg s⁻¹ in 0.3-10.0 keV energy band. Two flares with X-ray luminosities of 1.2 × 10²⁹ and 1.1 × 10²⁹ erg s⁻¹ were detected during the observation, where temperature corresponding to hot component are increased to 11.3 and 9.6 MK, respectively. The loop length is estimated of the order of 1010 cm for both flares. We have also derived other physical parameters of flaring plasma using the loop scaling laws.