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| NASA’s James Webb Space Telescope has provided an extremely detailed view of Herbig-Haro 211, a young star analogous to our Sun. This nearby star is surrounded by gas and dust which is propelled outward at high speeds due to the stellar winds or jets of gas from the new star. The image taken by Webb showcases a series of bow shocks to the southeast and northwest, as well as a narrow bipolar jet that powers them. Webb was also able to detect molecules such as molecular hydrogen, carbon monoxide and silicon monoxide, which are excited by the turbulent conditions and emitting infrared light. These molecules provide an interesting map of the structure of the outflows of Herbig-Haro 211, giving unprecedented detail of this infantile sun-like star. |
Herbig-Haro (HH) objects are luminous regions surrounding newborn stars, formed when stellar winds or jets of gas spewing from these stars form shock waves colliding with nearby gas and dust at high speeds. This image of HH 211 from NASA’s James Webb Space Telescope reveals an outflow from a Class 0 protostar, an infantile analog of our Sun. Infrared imaging is very effective when studying such stars and their outflows, since they are usually still embedded within the gas from the molecular cloud they formed in. The infrared emission of the outflows can penetrate the gas and dust, making HH 211 an ideal target for observation with Webb’s sensitive infrared instruments. Webb can collect infrared light emitted by molecules excited by the turbulent conditions such as molecular hydrogen, carbon monoxide, and silicon monoxide to map out the structure of the outflows.
The image of HH 211 presents a detailed view of bow shocks located at the southeast (lower-left) and northwest (upper-right) as well as a narrow bipolar jet that powers them. The resolution of this image is roughly 5 to 10 times higher than any previous images of HH 211, offering unprecedented detail. The inner jet is observed to “wiggle” with symmetric mirroring on either side of the central protostar, which supports earlier observations on smaller scales and suggests that the protostar may in fact be an unresolved binary star. Observations from ground-based telescopes have revealed giant bow shocks moving away and towards us, cavity-like structures in shocked hydrogen and carbon monoxide, as well as a knotty and wiggling bipolar jet in silicon monoxide. Comparing this to more evolved protostars with similar outflows, researchers have determined that the outflow of HH 211 is relatively slow.
The team measured the velocities of the innermost outflow structures to be roughly 48-60 miles per second (80-100 kilometers per second). However, there was a significantly smaller difference in velocity between these structures and the leading material they were colliding with, which was a shockwave. Through their research, the scientists concluded that outflows from the youngest stars, like that in the center of HH 211, were mostly comprised of molecules due to the comparatively low shock wave velocities not being powerful enough to break the molecules apart into simpler atoms and ions.
