Astronomers discover new nebula with evolving stars underneath its dust: Reports

Marking a new cosmic discovery, an international team of astronomers has discovered a new kind of nebula around a binary star system. Led by Stefan Kimeswenger from the Innsbruck University in Austria, the team has named the entity galactic emission nebula consisting of the binary star YY Hya. For the unversed, a nebula is a giant cloud of dust and gas in space and some of them are formed from the gas and dust emerging from the explosion of a dying star, such as a supernova. Interestingly, nebulae can also be called cosmic factories as their dust churns out infant stars. 

More about the nebula

Lead author Kimeswenger revealed that the diameter of the main cloud of this nebula is 15.6 light-years across, which makes it almost 1 million times larger than the distance of the Earth to the Sun. Besides, the galactic emission nebula resides slightly above the Milky Way and its fragments are as much as 39 light-years apart. According to the experts, the nebula was able to develop undisturbed by other clouds in the surrounding gas owing to its location over the Milky Way.

The discovery of the nebula is part of a study based on data gathered by amateur astronomers years ago, as per the Innsbruck University's official report. Now published in the journal Astronomy & Astrophysics, the study is titled "YY Hya and its interstellar environment', after the binary star system. The YY Hya is the system that is composed of a K dwarf star and a hot white dwarf (WD) partner and currently is a fully developed shell of a common envelope system (CE). 

"Toward the end of their lives, normal stars inflate into red giant stars. Since a very large fraction of stars are in binary stars, this affects the evolution at the end of their lives. In close binary systems, the inflating outer part of a star merges as a common envelope around both stars. However, inside this gas envelope the cores of the two stars are practically undisturbed and follow their evolution like independent single stars", Kimeswenger explained in an official press release. Shedding more light on the gas enveloping the stars, Kimeswenger said that they are extremely important for studying the evolution of stars in their final phase and how they sprinkle heavy elements into their surrounding. It is worth mentioning that the nebula's existence was confirmed after combining observational data from the Chile-based Chilescope observatory, the Spitzer Space Telescope and NASA's TESS over two decades. 

Interestingly, a model created by scientists based on the observations has revealed that the two stars orbit each other extremely closely in only 8 hours and 2 minutes. Besides, the white dwarf’s temperature is about 66,000 Celsius whereas the K dwarf is burning at about 4400 degrees Celsius.

Image: Innsbruck University