SA scientists discover Milky Way’s starry secrets
JOBURG - The first known stars in the flared disk of the Milky Way galaxy have been discovered by a team of astronomers working in South Africa.
According to Prof. Patricia Whitelock of the South African Astronomical Observatory in Sutherland, Northern Cape, the stars are situated at the far side of our galaxy, 80 000 light years from earth, and beyond the Galactic Centre.
Johannesburg Planetarium director, Dr Claire Flanagan, responded to the discovery of the stars, known as Cepheid variables, with enthusiasm.
“We love this kind of story, because it involves people working in South Africa, using our telescopes to discover something that is exciting and easy enough to include in our shows,” she said.
“We love telling children about these things.”
The discovery was made by Prof. Michael Feast (University of Cape Town, South African Astronomical Observatory), Dr John Menzies (South African Astronomical Observatory), Prof. Patricia Whitelock (University of Cape Town, South African Astronomical Observatory), and Dr Noriyuki Matsunaga (University of Tokyo, Japan).
Whitelock highlighted the importance of the discovery in the quest of astronomers to understand the universe.
“Stars like these will allows astronomers to test theoretical ideas about how galaxies formed,” she said.
“These stars, which are close to the effective edge of the Milky Way, will help astronomers trace the distribution of the very mysterious dark matter. [It] is known to be an important component of all galaxies, but its nature and distribution remain elusive.”
The team made use of the Southern African Large Telescope and the Infrared Survey Facility at the Sutherland observatory site to calculate the distances of the stars and their locations and movement within the galaxy.
“The majority of stars in our galaxy… are distributed in a flat disk. Early in the 21st century, radio astronomers discovered that hydrogen gas, of which the galaxy contains a great deal, flared away from the disk at large distances from the Galactic Centre,” she said.
“But until now no one knew that stars did the same thing.”
Flanagan said the stars were not visible to the naked eye.
“If you want to look towards them, you would need to look just above the ‘spout of the teapot’ – Sagittarius,” she said.
The planetarium hosts educational shows on weekends that offer tours of the constellations and our night skies, aimed at various age groups.
Details: 011 717 1390; www.planetarium.co.za; www.saao.ac.za
