The following is a progress report on the long-term coronal ( T \sim 1 MK ) activity of \alpha Centauri A ( HD 128620 : G2 V ) and B ( HD 128621 : K1 V ) .
Since 2005 , Chandra X-ray Observatory has carried out semiannual pointings on AB , mainly with the High Resolution Camera ( HRC-I ) , but also on two occasions with the Low-Energy Transmission Grating Spectrometer ( LETGS ) , fully resolving the close pair in all cases .
During 2008–2013 , Chandra captured the rise , peak , and initial decline of B ’ s coronal luminosity .
Together with previous high states documented by ROSAT and XMM-Newton , the long-term X-ray record suggests a period of 8.2 { \pm } 0.2 yr , compared to 11 yr for the Sun ; with a minimum-to-peak contrast of 4.5 , about half the typical solar cycle amplitude .
Meanwhile , the A component has been mired in a Maunder-Minimum-like low state since 2005 , initially recognized by XMM-Newton . But now , A finally appears to be climbing out of the extended lull .
If interpreted simply as an over-long cycle , the period would be 19.1 { \pm } 0.7 yr , with a minimum-to-peak contrast of 3.4 .
The short X-ray cycle of B , and possibly long cycle of A , are not unusual compared with the diverse ( albeit much lower amplitude ) chromospheric variations recorded , for example , by the HK Project .
Further , the deep low state of A also is not unusual , but instead is similar to the L _ { X } / L _ { bol } of the Sun during recent minima of the sunspot cycle .

( Note : This preprint includes one additional Chandra HRC-I pointing , in 2013 December , which was carried out after the final revision was submitted to the Journal .
The new X-ray points are consistent with the long-term trends and do not affect any of the quantitative conclusions . )