NGC 7129 through Webb's eyes: a cosmic cauldron

Every so often a new James Webb image stops me in front of the screen, and this time it was NGC 7129, a stellar nursery about 3,300 light-years from Earth. The telescope, sensitive to infrared, can look past the dust. The region had already been observed by Spitzer, now retired, but at much lower resolution.

At the centre is LkHα 234, a pre-main-sequence star with between 5 and 8 times the mass of the Sun: the most massive and mature star in the whole area. On the left opens a golden cavity about 3.5 light-years across, carved by the outflows of matter the star ejected in an earlier phase. The colour carries a precise meaning: warm atomic hydrogen appears golden, while colder molecular hydrogen appears red.

Inside the cavity are other pre-main-sequence stars, whose stellar winds carve smaller shock arcs and hollows. At the edges, where hydrogen molecules are split into atoms, a photodissociation region forms. On the right side, younger protostars are wrapped in dense, lumpy matter, and their superheated jets generate shock waves that sometimes overlap.

In the upper left is the detail I liked most: a protostar with a doughnut-shaped disc casts a shadow across a blue nebula, a structure similar to the so-called Bat Shadow already seen by Hubble.

What I find fascinating is that in a single shot you can read several generations of stars, from the most mature to the newborns still hidden in the dust. The image is credited to NASA, ESA, CSA and STScI, with processing by Alyssa Pagan.

Source: Media INAF