Newborn stars surround a planet-forming disk 450 million light years away

The James Webb Space Telescope’s (JWST) picture of the month for February 2025 is showing off the power of planet formation. The space telescope recently honed in on protoplanetary disk HH30. It is about 450 million light years away from Earth in the dark cloud LDN 1551 in the Taurus Molecular Cloud.

HH30 is considered a Herbig-Haro object–luminous regions that are surrounded by newborn stars, or protostars. These celestial objects form when jets of gas spewing from these newborn stars called stellar winds create shockwaves as they collide with gas and dust at high speeds. Protoplanetary disks like HH30 are where new planets can eventually form.

According to the European Space Agency (ESA), HH 30 is of particular interest to astronomers. It is considered a standard model of an edge-on disk. Understanding what is going on in these disks can help astronomers study how dust grains in space drift and settle, eventually building entire planets.

In the new image, an international team of astronomers used the JWST to investigate HH30 in greater detail. They combined JWST’s observations with those from the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA).

This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month presents HH 30 in unprecedented resolution. This target is an edge-on protoplanetary disc that is surrounded by jets and a disc wind, and is located in the dark cloud LDN 1551 in the Taurus Molecular Cloud. Herbig-Haro objects, like HH 30, are luminous regions surrounding newborn stars (known as protostars). They form when stellar winds or jets of gas spewing from these newborn stars form shockwaves as they collide with nearby gas and dust at high speeds. HH 30 is of particular interest to astronomers. In fact, the HH 30 disc is considered the prototype of an edge-on disc, thanks to its early discovery with the NASA/ESA Hubble Space Telescope. Discs seen from this view are a unique laboratory to study the settling and drift of dust grains. An international team of astronomers have used Webb to investigate the target in unprecedented detail. By combining Webb’s observations with those from the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA), the team was able to study the multiwavelength disc appearance of the system and its dynamic structures. These Webb observations were taken as part of the Webb GO programme #2562 (PI F. Ménard, K. Stapelfeldt), which aims to understand how dust evolves in edge-on discs like HH 30. Combined with the keen radio-wavelength eyes of ALMA, these observations show that large dust grains must migrate within the disc and settle in a thin layer. The creation of a narrow, dense layer of dust is an important stage in the process of planet formation. In this dense region, dust grains clump together to form pebbles and eventually planets themselves. In addition to the behaviour of dust grains, the Webb, Hubble, and ALMA images reveal several distinct structures that are nested within one another. Emerging at a 90-degree angle from the narrow central disc is a high-velocity jet of gas. The Webb data showed that clumps of gas within — A close-in image of protoplanetary disc HH 30. Parts of the image are labelled “Jet” (above and below the disc), “Conical Outflow”, “Possible Spiral”, “Dark Lane”, “Disk”, and “Tail”. A scale marker in the bottom-left is labelled “300 au”; this is a little wider than the disc itself, but less wide than the conical outflows above and below the disk. CREDIT: ESA/Webb, NASA & CSA, Tazaki et al. ESA/Webb, NASA & CSA, Tazaki et

The long-wavelength data from ALMA traces the location of dust grains that are only a few millimeters. The shorter-wavelength infrared data from JWST shows the distribution of even smaller dust grains–only one millionth of a meter across or the size of a single bacterium. The large dust grains are concentrated towards the center of the disk and the small grains are more widespread.

The observations were taken as part of the Webb GO program #2562. This project aims to understand how dust evolves in edge-on disks like HH30. When combined with radio-wavelength views from ALMA, these observations show that large dust grains must first migrate within the disk and then settle in a thin layer. The formation of a narrow–yet dense–layer of dust is an important stage during planet formation. This dense region is where dust grains can clump together to create pebbles and then eventually entire planets.

In addition to the behavior of dust grains, the new images show several distinct structures that are all nested within one another. A high-velocity jet of gas emerges from the narrow central disk. That narrow jet is surrounded by a wider, cone-shaped outflow. A wide nebula that reflects light from the young star encloses this outflow.
Together, this shows that HH 30 is a dynamic location and that massive jets and tiny dusts all play a role in building new planets.