Hubble revisits Trifid Nebula jet

Stars form inside cold clouds of gas and dust, and some of the youngest ones fire out narrow jets like pressure-release valves. Hubble’s new Trifid Nebula image shows one of those jets after a 29-year gap. (science.nasa.gov) (esa.int) NASA and the European Space Agency released the image on April 20 to mark Hubble’s 36th anniversary, ahead of the telescope’s April 24 launch anniversary. The target is a small part of the Trifid Nebula, also called Messier 20, about 5,000 light-years away in Sagittarius. (science.nasa.gov 1) (science.nasa.gov 2) The main feature is Herbig-Haro 399, a jet of plasma thrown off by a young protostar buried in brown dust. In astronomy, a Herbig-Haro object is the glowing streak made when that outflow slams into surrounding gas. (science.nasa.gov 1) (science.nasa.gov 2) Hubble first imaged this patch in 1997 with the Wide Field and Planetary Camera 2. The 2026 revisit used Wide Field Camera 3, which has a wider field of view and higher sensitivity than the older instrument. (science.nasa.gov 1) (science.nasa.gov 2) That long baseline lets astronomers compare the two pictures directly and watch the outflow change on human timescales. NASA and ESA said the repeated imaging can be used to measure the jet’s speed and how much energy the protostar is dumping into nearby gas. (science.nasa.gov) (esa.int) The image also shows a suspected counterjet, traced as jagged orange and red lines running down the back of the dusty structure. Nearby, another young star sits at the tip of a darker triangular horn with a tiny jet of its own. (esa.int) The wider cloud has been shaped for at least 300,000 years by several massive stars outside Hubble’s frame. Their ultraviolet radiation and winds have blown a bubble that compresses gas and dust and sets off new rounds of star formation. (science.nasa.gov) (esa.int) In the older 1997 image, Hubble described two finger-like jets roughly three-quarters of a light-year long protruding from a dense cloud. In the new view, the same region is sharper, wider, and detailed enough to track how the jet system has shifted over nearly three decades. (science.nasa.gov) (science.nasa.gov) Hubble’s Trifid revisit is less about a single pretty picture than a before-and-after record of a star still taking shape. After 29 years, the telescope is showing that at least some parts of a nebula do not wait for geologic time to move. (science.nasa.gov) (esa.int)