giant red star tagged posts

Credit: ALMA (ESO/NAOJ/NRAO); NASA/ESA Hubble; NRAO/AUI/NSF

An ancient, red giant star in the throes of a frigid death has produced the coldest known object in the cosmos – the Boomerang Nebula. How this star was able to create an environment strikingly colder than the natural background temperature of deep space has been a compelling mystery for more than two decades. The answer, according to astronomers using ALMA may be that a small companion star has plunged into the heart of the red giant, ejecting most the matter of the larger star as an ultra-cold outflow of gas and dust.

This outflow is expanding so rapidly – about 10 times faster than a single star could produce on its own – that its temperature has fallen to less than 0.5 K (-458.5F)...

An image of LX Cyg and its surroundings, obtained with the 80cm telescope at the University of Vienna Observatory. Credit: Stefan Uttenthaler et al./University of Vienna

A carbon star is a giant red star nearing the end of its life, with an atmosphere containing more carbon than oxygen. LX Cygni could be an interesting example of an object that is currently in the process of transitioning into a carbon star. “These observations are important to understand the chemical evolution of the universe, because most of the carbon in the universe is thought to come from stars just like LX Cygni,” Uttenthaler said.

Most of the carbon in our bodies comes from an earlier generation of stars such as LX Cygni...