Astronomers are watching the astronomical equivalent of an instant replay of a spectacular outburst from the unstable, behemoth double-star system Eta Carinae, which was initially seen on Earth nearly 170 years ago. Astrophysicists affiliated with UC Santa Barbara and Las Cumbres Observatory Global Telescope Network (LCOGT) contributed to the study.
Dubbed the “Great Eruption,” the outburst lasted from 1837 to 1858 and temporarily made Eta Carinae the second brightest star in the sky. But luckily for today’s astronomers, some of the light from the eruption took an indirect path to Earth and is just arriving now. The wayward light was heading in a different direction, away from our planet, when it bounced off dust lingering far from the turbulent stars and was rerouted to Earth, an effect called a “light echo.” Because of its longer path, the light reached Earth 170 years later than the light that arrived directly.
Pre print: http://arxiv.org/pdf/1112.2210.pdf