This plot shows the distance versus the age of brown dwarfs with disks that have parallaxes from Gaia DR2, are in known moving groups within 250 parsecs, and have readily available masses in the literature. As you can see, W1200-7845 is shown with a large star, and it is youngest brown dwarf disk within 102 parsecs. The other nearby brown dwarf disks are all in older moving groups, meaning they are not as bright and not as easily seen in detail. Also, from this graph, you can see that W1200-7845 is in a unique age range that connects the very young brown dwarfs to brown dwarfs around the age that their disks should start to dissipate (~10 Myr).
OU Graduate Student Maria Schutte Presents Findings on Young, Nearby Brown Dwarf With a Disk at American Astronomical Society Conference
University of Oklahoma graduate student Maria Schutte presented her findings on the discovery of the closest brown dwarf with a disk that is younger than 5 million years old Tuesday as part of a virtual briefing at the 236th meeting of the American Astronomical Society.
Schutte, a graduate student in the Homer L. Dodge Department of Physics and Astronomy at OU, is a part of associate professor Dr. John Wisniewski’s research team. The findings were made as part of NASA Goddard’s Disk Detective project, led by Dr. Marc Kuchner.
“We discovered the youngest brown dwarf disk within 102 parsecs (332 light years) of the Sun, putting W1200-7845 in the solar neighborhood,” said Schutte. “There are not many examples of young brown dwarfs so close to the Sun, so W1200-7845 is an exciting discovery.”
A brown dwarf is a substellar object that ranges in mass from about 13-80 times the mass of Jupiter. Unlike our Sun, brown dwarfs do not have enough mass to sustain hydrogen fusion in their cores, so they are distinct from higher mass stars. Brown dwarfs are the connection between stars and planets so understanding them is key to understanding the formation and evolution of both stars and planets.
Objects like the one discovered are important because of their youth and proximity. Youth is important in order to fully understand brown dwarfs because researchers need to understand how they are formed and how they evolve. Proximity is important because as brown dwarfs are lower in mass, they are inherently less bright, so the closer they are the easier it is to see these objects in more detail.
As W1200-7845 is in the Epsilon Chamaeleontis moving group, researchers know the age of W1200-7845 to be around 3.7 million years old. This age makes W1200-7845 a young brown dwarf, and researchers were able to confirm that W1200-7845 has the presence of a circumstellar disk, which is important in terms of understanding how brown dwarfs form and evolve in their early stages.
Being currently the youngest brown dwarf within the solar neighborhood, it should be possible to resolve the disk around W1200-7845 to within a few astronomical units using larger radio interferometers. Being able to see a young disk with that amount of resolution would allow for an unprecedented look at a key time in the evolution of brown dwarf disks.
“W1200-7845 is in a moving group that is about 4 million years old, which puts it at an ideal age to be a benchmark object in terms of investigating the formation and early evolution of brown dwarfs,” said Schutte. “I’ve been interested in learning more about physics and the universe since high school, so to be able to be a part of the discovery of such an exciting object for my first publication is really a dream come true.”
Disk Detective is a NASA citizen science project that uses optical and near infrared images to find new disk candidates. These disk candidates are possibly home to extrasolar planets. Citizen science is effective for this type of research because the most effective way to search for these systems is by visually inspecting the images of the objects in multiple wavelengths. In Disk Detective 1.0, citizen scientists classified and vetted over 400,000 objects from a NASA infrared survey.
A follow-up citizen science project, Disk Detective 2.0, launched on June 1. With Disk Detective 2.0, researchers will be classifying and vetting even more potential circumstellar disk candidates, and people at home can help find more objects with little to no training. To join the project and help NASA discover more new disks, visit diskdetective.org
“Disk Detective is a NASA citizen science project that uses the power of thousands of people to visually inspect images of possible disk candidates in multiple wavelengths of light,” said Schutte. “Disk Detective 1.0 enabled uncommon systems like this one to be discovered, and with the launch of Disk Detective 2.0 the public has a great chance of helping us find more exciting objects like W1200-7845.”
This figure shows W1200-7845’s spectral energy distribution (SED). This SED allow us to see that there is an excess of light coming from W1200-7845 at longer (infrared) wavelengths. The black line shows what would be expected of a brown dwarf with no disk present while the gray points show what we observed. This excess shows that W1200-7845 has a disk of warm dust and gas surrounding it.