It seems that brown dwarfs also regularly have a companion.

If we take our sun as an example, you would think that stars often live alone. But nothing is less true. Most stars in the Milky Way are not like our sun. In fact, it is thought that about 60 percent of all stars are in a binary star system. Double stars are actually very common. But what about brown dwarfs?

More about brown dwarfs
The brown dwarf is an odd one out. These celestial bodies have a mass that is less than that of a star, but much greater than that of a gas giant. Because brown dwarfs form in the same way as a star, but are too small for nuclear fusion, these celestial bodies are also called ‘failed stars’. It means they don’t have enough mass to “ignite” and shine like other stars. Instead, they fuse relatively small stocks of a heavier atomic version of hydrogen: deuterium. This process is less efficient and the light from brown dwarfs is therefore much weaker than that from stars.

Relatively little is known about brown dwarfs. And that’s not surprising because of their dimness and small size. This makes them very difficult to detect. Thanks to sensitive telescopes, astronomers have revealed several thousand brown dwarfs. But only a small portion are known to reside in a binary system. In short, because brown dwarfs are so difficult to observe, we don’t really know how often they have companions.

citizen science

To answer that question while expanding our understanding of brown dwarfs, astronomers in a new study the help of citizen scientists. Volunteers from Backyard Worlds — a global network of more than 100,000 citizen scientists — bent over countless telescope images to identify the subtle motion of a brown dwarf against background stars. Despite the possibilities of machine learning and supercomputers, the human eye is still the sharpest when it comes to recognizing moving objects in telescope images.

“It Backyard Worldsproject has created a diverse community of talented volunteers,” said Aaron Meisner, astronomer and co-founder of Backyard Worlds† “150,000 volunteers around the world participated in the project, including several hundred ‘super users’ who carry out ambitious research projects.”

34 ultra-cool brown dwarfs

One of these ‘super sleuths’ is citizen scientist Frank Kiwy. Using the NOIRLab Source Catalog DR2 he searched some 4 billion celestial bodies, looking for brown dwarfs with companions. And with success. Because his intensive research led to the discovery of 34 ultracool brown dwarfs that can be found in binary systems and are accompanied by a bright star or white dwarf. A special achievement. This means that the number of known brown dwarf stars without fear of commitment has even doubled.

Insight

Thanks to the citizen scientist, astronomers can better understand the personality of brown dwarfs. For example, the discovery could help determine whether brown dwarfs are more closely related to large planets or undersized stars. In addition, it could provide more insight into how galaxies evolve over time.

Astronomers are therefore very grateful to Kiwy. “The discovery was made by an amateur astronomer who has mastered astronomical data data,” Meisner concluded. “Modern astronomical archives contain a vast wealth of data and often contain great discoveries just waiting to be noticed.” So it means everyone can participate in groundbreaking research and share in the joy of a new, cosmic discovery. In any case, Kiwy is enthusiastic. “I love it Backyard Worldsproject,” he says. “Once you get the workflow mastered, you can dive much deeper into the subject. If you are a person who is curious and not afraid to learn something new, then this might be for you.”