AN AGEING star鈥檚 fluttering pulse has changed its beat. This may be a rare
glimpse of stellar evolution in action, astronomers say in this week鈥檚
Astrophysical Journal Letters (vol 489, p 55).
Christine Clement of the University of Toronto and her colleagues observed
the star V79, about 30 000 light years away. An 鈥淩R Lyrae variable star鈥�, it
gets brighter and dimmer twice a day as it throbs.
Clement says the star鈥檚 beat has changed since the 1970s. The star used to
pulse in a simple way, but now it has picked up complicated overtones. 鈥淣obody
has ever seen a pure mode changing to a double mode,鈥� says Clement. Because the
mode depends on temperature, the switch may help astronomers to pinpoint V79鈥檚
evolutionary stage.
Advertisement