Herbig-Haro (HH) objects have always been of immense fascination in the field of astronomy. Acting as radiant neon signs of stellar infancy, these objects provide rare insights into the very early moments of a star’s life. The latest image from NASA’s James Webb Space Telescope (Webb) has now thrown light on an especially intriguing HH object – HH 211, giving us a glimpse into the early life of a Sun-like star.
HH objects are bright regions that emerge around nascent stars. Their brilliance is a result of stellar winds or gas jets that the newborn stars eject. These winds and jets, travelling at astonishing speeds, collide with the neighboring gas and dust, creating shock waves in the process.
HH 211 is particularly captivating because it presents an outflow from what’s referred to as a Class 0 protostar. This protostar stands as an early representation of what our very own Sun might have looked like when it was only a few tens of thousands of years into its existence. Currently, it holds just 8% of the Sun’s present-day mass, though it is projected to mature into a Sun-like star in the future.
Infrared imaging has emerged as a revolutionary tool in the observation of these stellar infants. The reason? Newborn stars are typically surrounded by the gas from the molecular cloud of their birth.
This gas, while protective, also obscures our view. Infrared imaging, however, can penetrate this veil. The infrared emission from the star’s outflows, as in the case of HH 211, is distinctly observable using Webb’s sensitive infrared instruments.
Webb’s image not only brings forward the HH 211 in incredible clarity, but it also captures the turbulence that surrounds it. Molecules such as molecular hydrogen, carbon monoxide, and silicon monoxide get excited amidst these turbulent conditions and release infrared light. This light, as captured by Webb, assists researchers in mapping the structure of these stellar outflows.
The clarity of the image from Webb is unmatched. It has a spatial resolution that’s about 5 to 10 times finer than any preceding images of HH 211. This unmatched precision showcases a series of bow shocks, with directions pointing to the southeast and northwest. Moreover, the image reveals a narrow bipolar jet that powers these shocks.
Intriguingly, there’s a noticeable “wiggle” in the inner jet. This symmetric wriggle on either side of the central protostar aligns with earlier observations and gives credence to the theory that the protostar could be an unresolved binary star.
The image also confirms certain observations made with ground-based telescopes. These previous observations had revealed giant bow shocks moving in opposite directions and structures resembling cavities in shocked hydrogen and carbon monoxide. Moreover, they captured a knotty and oscillating bipolar jet in silicon monoxide.
With the added data from Webb, researchers have gained new insights into HH 211’s outflows. Compared to similar protostars that are more evolved, HH 211’s outflow is slower. Measurements indicate velocities ranging between 48-60 miles per second. Yet, when this outflow collides with the leading material, the shockwave’s velocity differential is minimal.
The comparatively low velocity of these shock waves offers an interesting revelation. The researchers posit that outflows from very young stars, such as the one at the center of HH 211, are predominantly molecular. The velocity of the shockwaves isn’t high enough to disintegrate these molecules into simpler atoms and ions.
In summary, the James Webb Space Telescope’s observations of HH 211 offer a comprehensive understanding of a Sun-like star’s early life. As technology and research advance, these insights become invaluable in painting a clearer picture of our universe’s intricate dynamics.
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