red giant star tagged posts

One of the brightest stars in the night sky, Betelgeuse, may not be on the brink of exploding as a supernova, according to a new study of the star’s brightening and dimming. Instead, recent research shows that the observed pulsing of the starlight is probably caused by an unseen companion star orbiting Betelgeuse.

Formally named Alpha Ori B, the “Betelbuddy” (as astrophysicist Jared Goldberg calls it) acts like a snowplow as it orbits Betelgeuse, pushing light-blocking dust out of the way and temporarily making Betelgeuse seem brighter. Goldberg and his colleagues present their simulations of this process in a paper accepted for publication in The Astrophysical Journal. The findings are published on the arXiv preprint server.

“We ruled out e...

Astronomers at the University of Sydney have found a slimmer type of red giant star for the first time. These stars have undergone dramatic weight loss, possibly due to the presence a greedy neighbour. Published in Nature Astronomy, the discovery is an important step forward to understanding the life of stars in the Milky Way – our closest stellar neighbours.

There are millions of ‘red giant’ stars found in our galaxy. These cool and luminous objects are what our Sun will become in four billion years. For some time, astronomers have predicted the existence of slimmer red giants. After finding a smattering of them, the University of Sydney team can finally confirm their existence.

“It’...

Another ancient star has been found lurking in the Milky Way. Around 35,000 light-years away, a red giant star named SMSS J160540.18–144323.1 was found to have the lowest iron levels of any star yet analysed in the galaxy.

This means that it’s one of the oldest stars in the Universe, probably belonging to the second generation of stars after the Universe burst into existence 13.8 billion years ago.

“This incredibly anaemic star, which likely formed just a few hundred million years after the Big Bang has iron levels 1...

The sky around W Hydrae, as seen in visible light. Credit: Digitized Sky Survey

A Chalmers-led team of astronomers has for the first time observed details on the surface of an aging star with the same mass as the Sun. The star is a giant, its diameter twice the size of Earth’s orbit around the Sun, but also that the star’s atmosphere is affected by powerful, unexpected shock waves. The research is published in Nature Astronomy on 30 October 2017. The new ALMA images show for the first time details on the surface of the red giant W Hydrae, 320 light years distant in the constellation of Hydra, the Water Snake.

W Hydrae is an example of an AGB (asymptotic giant branch) star. Such stars are cool, bright, old and lose mass via stellar winds...