Astronomers have uncovered new insights into Herbig-Haro objects, small nebulae found in star-forming regions. These objects mark where gas from young stars heats up due to shockwaves. A prime example is HH 30, where gas flows out as a narrow jet from a star hidden behind an edge-on protoplanetary disc.
Discovered early by the NASA/ESA Hubble Space Telescope, HH 30 is a special focus for astronomers. Its disc, visible edge-on, is ideal for studying dust grain behavior.
An international team used the Webb telescope to examine HH 30 closely. They could study the system’s disc in multiple wavelengths by combining data from Webb, Hubble, and the Atacama Large Millimeter/Submillimeter Array (ALMA).
ALMA’s long-wavelength data showed millimeter-sized dust grains in the disc’s central plane. In contrast, Webb’s shorter-wavelength infrared data revealed smaller dust grains, the size of bacteria, spread more widely.
Webb’s observations, part of the Webb GO program #2562, aimed to understand dust evolution in discs like HH 30. The findings highlight that large dust grains migrate and settle in a thin layer, which is crucial for planet formation. In this dense region, dust grains clump together to form pebbles and planets.
Revealing Complex Structures:
Combined images from Webb, Hubble, and ALMA unveiled intricate structures within HH 30:
- A high-velocity gas jet emerges at a 90-degree angle from the central disc.
- A cone-shaped outflow encircles this jet.
- A broader nebula, reflecting the star’s light, encloses the outflow.
These findings highlight HH 30 as a dynamic environment where dust grains and gas jets contribute to new planet formation. This dynamic setting offers astronomers a unique opportunity to study the processes leading to planet formation.
