Measuring the temperatures of red giants is actually pretty tricky

Red giant stars are, well, red and giant. But astronomers have always had difficulty estimating their temperatures due to their complex and turbulent atmospheres. Without an accurate gauge of their temperatures, it's difficult to tell when they will end their lives in gigantic supernova explosions. Now, a team of astronomers has developed a more effective technique for taking the temperature of red giants based on the amount of iron in the stars.