Australasian Science: Australia's authority on science since 1938

Astronomers Locate Oldest Known Solar System

By David Reneke

At 11.2 billion years of age, Kepler-444 is the oldest star with Earth-like planets ever found.

The full text of this article can be purchased from Informit.

A Sun-like star with orbiting planets, dating back to the dawn of the galaxy, has been discovered by an international team of astronomers. At 11.2 billion years old it is the oldest star with Earth-sized planets ever found, and proves that such planets have formed throughout the history of the universe.

The star, Kepler-444, hosts five planets smaller than Earth, with sizes varying between those of Mercury and Venus. “We’ve never seen anything like this – it is such an old star and the large number of small planets make it very special,” said Dr Daniel Huber from the University of Sydney’s School of Physics. “It is extraordinary that such an ancient system of terrestrial-sized planets formed when the universe was just starting out, at a fifth its current age.”

Kepler-444 is two-and-a-half times older than our solar system, which is only a youthful 4.5 billion years old. “This tells us that planets this size have formed for most of the history of the universe and could provide scope for the existence of ancient life in the galaxy,” Huber said.

The research team used “asteroseismology” to determine the age of the star and planets. This technique measures oscillations of the host star caused by sound waves trapped within it. These lead to miniscule pulses in the star’s brightness, allowing researchers to measure its diameter, mass and age.


The full text of this article can be purchased from Informit.