Recent news from the Hubble Space Telescope website is telling us about a great big “nasty star” in the galaxy that is cannibalizing from its smaller neighbor and generally not behaving as a good Wolf-Rayet star is supposed to.
Wolf-Rayet Stars on their Way to Supernova
A Wolf-Rayet star is a giant star, more than 20 times larger than our own Sun and they are in the last stages of their lives before going supernova. These types of stars are running out of fuel. The last elements it starts to burn have more atoms and thus create more radiation and heat. Solar winds blowing from the sun can travel up to 5.4-million miles per hour. Eventually, the winds strip off the outer layers of gas, leaving the core, which succumbs to gravity, creating a supernova.
What scientists normally see with a Wolf-Rayet star is that it is paired with a smaller, unseen star that it leeches fuel from in the form of hydrogen, helium, oxygen and so forth. These stars puff up as they begin to lack hydrogen for fuel and become susceptible to gravitational stripping. The stars expand as the elements holding it together start to be burned as fuel. The process of gases leeching away usually creates an image of twin hemispheres of gas emanating from opposite ends of the star.
The NaSt1 “Nasty Star”
In the case of the nasty star, pictures from NASA’s Hubble Space Telescope are showing a disk of gas that is more pancake-shaped surrounding the star. The circle of gas is estimated to be 2-trillion miles across. That is about 1,000 times larger than our own solar system.
The nasty star got its nickname from the official name of NaSt1, which is the designation in honor of the two astronomers who first spotted the star in 1963, Charles Stephenson and Jason Nassau. Researchers have more recently been observing the nasty star as it provides unusual circumstances. In universal time, this phenomenon is short lived, with the gas disk travel only being visible for perhaps ten-thousand years and there aren’t many examples around for study.
Reason for the Strange Disk Shape
Astronomer Jon Mauerhan, the NaSt1 study leader, from the University of California-Berkeley Department of Astronomy, explains that this new information from Hubble shows what is likely a pair of Wolf-Rayet stars wherein the larger star is siphoning hydrogen from the smaller one, and the occurrence is extremely rare. He states that the larger star cannibalizing the smaller one makes the nasty star nickname a fitting one. Studying this event of aggressive expansion from the stars can help astronomers understand how stars are formed and how they die.
The results of the research were recently published in the Monthly Notices of the Royal Astronomical Society’s online edition.
