Infrared images taken by the James Webb telescope shed light on stars and galaxies in the Large Magellanic Cloud.
Thousands of never-before-seen young stars are crowded into a stellar nursery called 30 Doradus, imaged by the Space Telescope NASA’s James Webb and nicknamed the tarantula nebula.
Because of the appearance of its dusty filaments in previous telescope images, the nebula has long been a favorite of astronomers studying star formation.
In addition to young stars, Webb reveals distant background galaxies, as well as the detailed structure and composition of the nebula’s gas and dust.
Just 161,000 light-years away in the Large Magellanic Cloud galaxy, the Tarantula Nebula is the largest and brightest star-forming region of the Local Group, the closest galaxies to our Milky Way. In addition, it is home to the hottest and most massive stars known.
The instruments to capture the Tarantula Nebula
The astronomers focused three of Webb’s high-resolution infrared instruments on the Tarantula.
Viewed with Webb’s Near Infrared Camera (NIRCam), the region resembles the house of a burrowing tarantula, covered with her silk.
The cavity of the nebula centered in the NIRCam image has been hollowed out by searing radiation from a cluster of massive young stars, which glow pale blue in the image.
Only the denser surrounding areas of the nebula resist erosion by the powerful stellar winds from these stars, forming pillars that appear to point toward the cluster.
These pillars contain forming protostars, which will eventually emerge from their dusty cocoons and take their turn to shape the nebula.
Webb’s Near Infrared Spectrograph (NIRSpec) caught a very young star doing just that. Astronomers previously thought that this star might be a bit older and that it is already he was in the process of clearing a bubble around himself.
However, NIRSpec showed that the star was just beginning to emerge from its pillar and still had an insulating cloud of dust around it. Without Webb’s high-resolution spectra at infrared wavelengths, this star-forming episode in action might not have been revealed, NASA reports.
The region takes on a different appearance when viewed in the longer infrared wavelengths detected by Webb’s Mid-Infrared Instrument (MIRI). Hot stars fade and cooler gas and dust glow.
Within the stellar nursery clouds, points of light indicate embedded protostars, which are still gaining mass.
While shorter wavelengths of light are absorbed or scattered by dust grains in the nebula and thus never reach Webb to be detected, longer mid-infrared wavelengths penetrate that dust, revealing finally a cosmic environment never seen before.
One of the reasons the Tarantula Nebula is interesting to astronomers is that it has a type of chemical composition similar to the giant star-forming regions seen at “cosmic noon” in the universe, when the cosmos was only a few few billion years and the star formation was at its peak.
Star-forming regions in our Milky Way galaxy are not producing stars at the same breakneck rate as the Tarantula Nebula, and have a different chemical composition.
This makes the Tarantula the closest example (that is, the easiest to see in detail) of what was happening in the universe when it reached its bright noon.
