Altair One is an inhabited planet encountered by the Kzinti at some point before 2366[1].[2]
According to the Kzin the local Altairans practiced a religion that taught them they could travel in time. After the Kzin landed an infantry unit to enslave the planet they found it empty of people. The Kzin speculate they committed mass suicide with disintegrators, although evidence of the disintegrators themselves was never found.[2]
It is unknown what happened with the planet afterwards.