Tag: red giant

A strange new type of star referred to by scientists as an “old smoker” has been discovered after a years-long astronomical study. 

According to four different studies recently published in Monthly Notices of the Royal Astronomical Society, these recently discovered stellar objects are essentially really large and very old stars that emit puffs of what appears to be smoke and dust after many decades of inactivity. 

These stars were discovered using a powerful giant telescope located deep in the mountains of Chile. Lead author of one study and co-author of the other three, Phillip Lucas, said that thus far, scientists are not completely sure what creates this effect in the old smoker stars. 

“Everything we have been able to learn about them suggests that this is a case of stars throwing off puffs of smoke—for reasons that we don’t fully understand,” Lucas said. “We weren’t sure if these stars were protostars starting an eruption, or recovering from a dip in brightness caused by a disc or shell of dust in front of the star — or if they were older giant stars throwing off matter in the late stages of their life,” Lucas said

Originally the studies were focused at finding newborn stars, oftentimes surrounded by dust and gasses making them hard to see. This is why the VISTA (Visible and Infrared Survey Telescope) in Chile, capable of seeing infrared light, was used to scan the skies for the stars other telescopes would not be able to see. As Dr. Zhen Guo, Fondecyt Postdoc Fellow at the University of Valparaiso in Chile and lead author of two studies explained, these newborn stars often help to form new solar systems over time. 

“Our main aim was to find rarely-seen newborn stars, also called protostars, while they are undergoing a great outburst that can last for months, years, or even decades,” Guo said. “These outbursts happen in the slowly spinning disc of matter that is forming a new solar system. They help the newborn star in the middle to grow, but make it harder for planets to form. We don’t yet understand why the discs become unstable like this,” Guo said.

The old smoker stars are a kind of red giant. Red giants are stars which have essentially expired, that is, they’ve run out of hydrogen fuel and have “died” in a sense. This often causes violent energy outbursts from the star for a while. Our own sun will go through this one day in the far off future, swallowing several of the inner planets in the course of its death according to NASA, though the fate of the Earth remains relatively unclear when this happens. Luckily, it’ll be several billion years before this occurs so it will more than likely be somebody else’s problem by then.  

The team of scientists involved with these studies found several red giants, 21 to be exact, that appeared to be a bit different than those found in the past. They chose seven of these stars to focus on and noticed unusual characteristics that puzzled them, most noticeably the smoke and dust they appeared to exert which is how they received the moniker ‘old smoker.’ 

“These elderly stars sit quietly for years or decades and then puff out clouds of smoke in a totally unexpected way,” said Dante Minniti, a professor in the department of physics at Andrés Bello University in Chile and coauthor on three of the studies, in a press release “They look very dim and red for several years, to the point that sometimes we can’t see them at all.”

Most of the stars the team studied were found near the center or the nucleus if you will of the Milky Way Galaxy, known as the innermost nuclear disc. Lucas explained that these newly discovered stars could potentially play a role in the way elements are distributed across the galaxies.

“Matter ejected from old stars plays a key role in the life cycle of the elements, helping to form the next generation of stars and planets,” Lucas said. “This was thought to occur mainly in a well-studied type of star called a Mira variable. However, the discovery of a new type of star that throws off matter could have wider significance for the spread of heavy elements in the Nuclear Disc and metal-rich regions of other galaxies.”