Circumbinary planets – planets that orbit two stars, like the fictional Star Wars planet Tatooine and its two suns – exist in the Universe and are sometimes referred to as Tatooine planets. Systems in which two stars orbit each other, called binary star systems, are incredibly common, comprising more than half of the stars in the Milky Way. But how does a binary system like this come about?
Researchers using the Stratospheric Observatory for infrared astronomy, (SOFIA) observed, along with several other observations, a 45 degree twist in the magnetic field of the L483 protobinary system.
SOFIA saw a twisted magnetic field around a protobinary star system – a very young binary star system that continues to grow. This gives a clue as to how the protobinary system came into being. The findings were published in Geophysical Research Letters.
When stars begin to form, they get most of their matter from a disk of dust and gas that surrounds them. A larger envelope of material surrounds and feeds the disc. From there, the binaries can emerge in two ways: far apart, where they grow in the envelope, or much closer together, where they grow in the disk.
There is a caveat, however. The binaries that form in the envelope can get closer to each other over time, so even if they look the same now, they haven’t necessarily always been that way.
“We think these protostars formed very far away, migrated and twisted their field as they approached each other,” said Erin Coxpostdoctoral fellow at Northwestern University who conducted the study.
This is where magnetic fields come in.
In the recent study, SOFIA observations – supported by data from the Atacama Large Millimeter Array (ALMA), the Pico dos Dias Observatory and archival data from the Herschel Space Observatory – found that the magnetic field in the formation cloud of star Lynds 483 (L483) is oriented east-to-west in its outer regions, but twists 45 degrees counterclockwise toward its center. ALMA confirmed that L483 contains two protostars and Herschel provided information on some of the physical properties of the region, while SOFIA and Pico dos Dias traced the shape of the magnetic field.
Because stars and their planets form around the same time, understanding how the protobinary came together tells astronomers what kinds of planets it may house.
“If we understand how protobinary stars formed, we’ll have a better understanding of how much material is in the disk, which is the material that provides planets with their masses,” Cox said. “We want to understand what our starting mass budget is for these planets.”
For example, the inward migration of protobinaries can enhance the movement of gas and dust around them, ejecting them out of the system. If too much material is blown out, only rocky Earth-like planets can potentially form, rather than gas giants, like Jupiter.
Being able to see these magnetic fields helps decipher the formation of the binary systems and, in turn, their associated Tatooine planets.
Additional resources: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL097786
SOFIA is a joint project of NASA and the German Space Agency at DLR. The DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA Ames Research Center in California Silicon Valley runs SOFIA program, science and mission operations in cooperation with the Space Research Association of Universities, headquartered in Columbia, Marylandand German SOFIA Institute of the University of stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. SOFIA reached full operational capability in 2014, and the mission will end no later than September 30, 2022. SOFIA will continue its regular operations until then.
About the USRA
Founded in 1969 under the auspices of the National Academy of Sciences at the request of the United States government, the Universities Space Research Association (USRA) is a nonprofit corporation dedicated to advancing science, technology, and engineering related to space. The USRA operates scientific institutes and facilities and conducts other major research and educational programs. USRA engages the academic community and employs in-house scientific leadership, innovative research and development, and project management expertise. More information about the USRA is available at www.usra.edu.
Legend: A subset of polarization vectors are superimposed on an image from the Lynds 483 Spitzer Space Telescope. SOFIA the data are indicated in red and in orange the vectors were obtained by the Pico dos Dias observatory. Green vectors show data obtained by the SHARC C-II polarimeter at Caltech’s Submillimeter Observatory in previous work, presented here as a scale comparison. Near the center of the image is a small yellow dot indicating the location of the binary protostars. The combined fields show twist as they approach the protostellar envelope, although they are parallel at larger scales.
Credit: L483: NASA/JPL-Caltech/J. To throw; Vectors: Cox et al. 2022, Chapman et al. 2013
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SOURCE Space Research Association of Universities