Approximately 200 light-years from the black hole located at the core of the Milky Way is a region that is unexpectedly less productive in star formation than scientists anticipated. This area, known as the Sagittarius C cloud, is filled with the necessary components to create stars, but it has not produced new stars at a high rate, despite potentially having already formed thousands. Researchers directed the James Webb Space Telescope, a collaboration between NASA and its European and Canadian space partners, at this enigmatic stellar nursery to investigate the reasons behind its low yield. Using its advanced infrared capabilities, the telescope provided a clearer picture.
The results, published in two papers in The Astrophysical Journal, offer new insights into why some star-forming regions may appear relatively ineffective. It is now believed by researchers that strong magnetic fields may be hindering star formation. John Bally, an astrophysicist at the University of Colorado Boulder, explained, “A big question has been, if there is so much dense gas and dust here, and we know stars form in these kinds of clouds, why are so few stars born in Sagittarius C?” He noted that for the first time, there is evidence that strong magnetic fields may be significantly obstructing star formation.
The Meerkat radio telescope in South Africa helps contextualize the Webb image, revealing Sagittarius C within an environment spanning 1,000 light-years. The inset Webb image covers about 44 light-years. The Webb telescope, designed to detect invisible light at infrared wavelengths, can penetrate clouds of cosmic dust and gas that block the view of extremely distant and dim light sources. One Webb scientist compared the telescope’s sensitivity to detecting the heat of a single bumblebee on the moon.
Scientists assert that understanding the processes occurring in Sagittarius C is crucial for comprehending star formation in general. Stars produce most of the chemical elements on Earth, including carbon and oxygen, which are vital for life. However, experts acknowledge that much remains to be learned about the universe’s star formation mechanisms.
The research identified two massive stars, each more than 20 times the mass of the sun, forming within Sagittarius C and releasing powerful jets of gas as they grow. Additionally, five smaller stars enveloped in dense dust were identified. The Webb telescope also discovered 88 peculiar structures composed of glowing hydrogen, believed to be shock waves caused by young stars expelling material into space. Researchers also found another nearby star-forming region with at least two developing stars.
Prior studies of Sagittarius C revealed numerous filamentous structures in the hot hydrogen gas surrounding the main star-forming cloud. It is thought that the magnetic forces from the Milky Way’s supermassive black hole, Sagittarius A*, are strong enough to counteract the force of gravity. This magnetic tension could be preventing the dense clouds from collapsing and forming additional stars. Samuel Crowe, a Rhodes Scholar at the University of Virginia who co-led the study, stated that Sagittarius C has proven to be a crucial laboratory for testing star formation theories. He remarked, “This discovery opens up new questions about how magnetic fields influence the birth of stars, both in our galaxy and beyond.”
