James Webb Space Telescope Feed Post

Mark McCaughrean | A timelapse movie of the HH212 protostellar jet

A timelapse sequence of four infrared images of the HH212 protostellar jet spanning 22 years, all taken in the 2.12 micron emission line of shocked molecular hydrogen. The images have been colourised using the "heat" look-up table. The jet seen here spans about 0.5 parsecs in length or about 1.6 light years. The first three images were taken using the infrared cameras ISAAC and HAWK-I on the European Southern Observatory Very Large Telescope (VLT) in 2000, 2007, and 20018, while the final image was made using NIRCam on the NASA/ESA/CSA JWST in November 2022. Although the registration in this movie is only rough (we can and will do much better!) and the spatial resolution of the JWST image far superior to the VLT images, the motions of the various knots and bowshocks in HH212 can be clearly seen. By measuring the motions over time, the expansion speed can be calculated: near the centre it is around 150 kilometres per second, slowing to around 100 km/s further out, and we also see clear deceleration on the righthand-side (towards the south). Including further bowshocks at roughly 1 parsec from the centre on either side, an overall dynamical lifetime of approximately 7,000 years can be calculated. To get the short movie to loop, play it in "lightbox mode", i.e. click the expansion arrows at top-right. Credit: NASA, ESA, CSA, ESO, Mark McCaughrean & Sam Pearson, CC BY-SA Image & Description by Mark McCaughrean