"The Songs of Distant Earth (1986), novel by Arthur C. Clarke. Scientists in the 1960s discover that the neutrino emissions from the Sun are far less than predicted by theory.It is soon confirmed that the Sun will go nova around the year 3600 CE. Humankind embarks on a massive project to send robot-tended human and other mammalian embryos to habitable worlds orbiting nearby stars. The first destination is Pasadena, a marginally viable planet of Alpha Centauri A... the next likely target was more than twice as far away. The voyage time to Sirius X would be over four hundred years; when the seeder arrived, Earth might no longer exist."