The Cycles of Alpha Centauri

The main AB pair of the nearby Alpha Centauri triple system has one of the most extensive X-ray records of any cosmic object, stretching over three decades. The primary, a Cen A (G2 V), is a near twin of the Sun, with a similarly soft (1-2 MK) corona. The secondary, a Cen B (K1V), is more active than the Sun, with a generally harder coronal spectrum. Here, spatially resolved measurements of the pair by Chandraʹs High Resolution Camera are compared, on a common basis, with previous pointings from ROSAT and XMM-Newton.