NASA released an image of a star that looks like a twinkling wreath. The image was clicked by NASA/ESA Hubble Space Telescope.
The brilliant star is a perfect example of a magnificent phenomenon called 'light echo,' according to NASA. A light echo is when light around the star seems to twinkle.
The giant star in the image is named RS Puppis. It is over ten times bigger than our Sun, and is around 15,000 times more luminous, according to a statement. RS Puppis belongs to a category of stars known as Cepheid variable.
Cepheid variable stars have consumed their main supply of hydrogen and are now unstable. They pulsate at regular intervals. RS Puppis brightens and diminishes over a period of six weeks. During its peak brightness, it illuminates the dust around it. The pulses appear to reverberate from the gas-dust cloud around the star, which is why it is called as a "light echo."
"As the star expands and brightens, we see some of the light after it is reflected from progressively more distant shells of dust and gas surrounding the star, creating the illusion of gas moving outwards. This reflected light has further to travel, and so arrives at the Earth after light that travels straight from star to telescope. This is analogous to sound bouncing off surrounding objects, causing the listener to hear an audible echo," the agency said in a statement.
Cepheid stars aren't just studied due to their pulsating nature, but also because they act as 'cosmic distance markers'. Back in 1912, an American astronomer named Henrietta Leavitt found that there is a relation between period of the pulses and the intrinsic brightness of the star.