Citizen Scientists Find a Star Escaping the Milky Way

August 20, 2024 by Mark Thompson

Collected at: https://www.universetoday.com/168167/citizen-scientists-find-a-star-escaping-the-milky-way/

Citizen science is such a great concept. Using the combined computing power of a gazillion (exaggeration) desktop and laptops to churn through data is an excellent and efficient way of analysing volumes of data. This has been shown yet again as a star has been identified to be hurtling out to intergalactic space! Most stars in the Milky Way are not travelling fast enough to be able to escape its immense gravity but the suspected brown dwarf is travelling at 1.5 million km/h, fast enough to escape. 

The concept of using members of the public to support scientific endeavours dates back further than you might think. One of the earliest examples can be seen in the 19th century when the Christmas Bird Count was launched by the Audubon Society in 1900. It encouraged members of the public to track bird populations. When it comes to space science projects like SETI@Home are among those that spring to mind. 

Another citizen science project ‘Planet 9’ was launched by Backyard Worlds and to date, it has 82,690 volunteers signed up. The goal is to hunt for possible distant planets in our Solar System or previously unidentified brown dwarfs in our solar neighbourhood. It takes images from NASA’s Wide-field Infrared Survey Explorer (WISE) and shares them with its volunteers who then study them for objects that are moving. 

While hunting for objects worthy of study, a team of volunteers; Martin Kabatnik, Thomas P.Bickle and Dan Caselden identified a fast moving object which became known by the catchy title CWISE J124909.08+362116.0. Observations were scheduled after its discovery by several ground based instruments that showed it was moving so fast that it will eventually escape the gravitational pull of the Milky Way, heading out to intergalactic space. It’s the first object with a mass smaller than or similar to that of a star that has been seen travelling at such eye watering speeds – 1.5 milllion km/h! To mark the citizen scientists contribution they are named as co-authors to the study which has recently been published in the Astrophysical Journal Letters. 

Quite what CWISE J1249 is remains a little bit of a mystery at the moment. It has a low mass suggesting either a low mass star or possibly a gas giant planet or maybe something in between known as a brown dwarf. It has also been found to have less iron and other metals in the core than other stars and brown dwarfs. The composition suggests it may be quite old and perhaps one of the first generations of stars from the Milky Way. If it is a brown dwarf then in itself it is not particularly rare. ‘Planet 9’ has discovered more than 4,000 of them alone but none are travelling at such a great speed that they will escape the Galaxy. 

It’s not just the nature of the object that is perplexing astronomers, its high speed to has been the subject of much debate. One theory suggests it could have been a part of a binary system with a white dwarf. The white dwarf would slowly accrete material from its companion leading to an explosion when the material reaches a critical point. This event may have provided the energy to accelerate the object out of the system and beyond.  Alternatively it may have been a part of a cluster which was ejected through gravitational interactions. 

Source : NASA Citizen Scientists Spot Object Moving 1 Million Miles Per Hour