Webb captures a cosmic tarantula

by European Space Agency

In this mosaic image stretching 340 light-years across, Webb’s Near-Infrared Camera 

(NIRCam) displays the Tarantula Nebula star-forming region in a new light, including tens 

of thousands of never-before-seen young stars that were previously shrouded in cosmic 

dust. The most active region appears to sparkle with massive young stars, appearing pale

 blue. Scattered among them are still-embedded stars, appearing red, yet to emerge from 

the dusty cocoon of the nebula. NIRCam is able to detect these dust-enshrouded stars 

thanks to its unprecedented resolution at near-infrared wavelengths. To the upper left of 

the cluster of young stars, and the top of the nebula’s cavity, an older star prominently 

displays NIRCam’s distinctive eight diffraction spikes, an artifact of the telescope’s structure

. Following the top central spike of this star upward, it almost points to a distinctive bubble

 in the cloud. Young stars still surrounded by dusty material are blowing this bubble, 

beginning to carve out their own cavity. Astronomers used two of Webb’s spectrographs to

 take a closer look at this region and determine the chemical makeup of the star and its 

surrounding gas. This spectral information will tell astronomers about the age of the 

nebula and how many generations of star birth it has seen. Farther from the core region of 

hot young stars, cooler gas takes on a rust color, telling astronomers that the nebula is 

rich with complex hydrocarbons. This dense gas is the material that will form future stars.

 As winds from the massive stars sweep away gas and dust, some of it will pile up and, 

with gravity’s help, form new stars. 

Credit: NASA, ESA, CSA, and STScI

Thousands of never-before-seen young stars are spotted in a stellar nursery called 30 Doradus, captured by the NASA/ESA/CSA James Webb Space Telescope. Nicknamed the Tarantula Nebula for the appearance of its dusty filaments in previous telescope images, the nebula has long been a favorite for 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

At only 161,000 light-years away in the Large Magellanic Cloud galaxy, the Tarantula Nebula is the largest and brightest star-forming region in the Local Group, the galaxies nearest to our Milky Way. It is home to the hottest, most massive stars known. Astronomers focused three of Webb's high-resolution infrared instruments on the Tarantula. Viewed with Webb's Near-Infrared Camera (NIRCam), the region resembles a burrowing tarantula's home, lined with its silk. The nebula's cavity centered in the NIRCam image has been hollowed out by blistering radiation from a cluster of massive young stars, which sparkle pale blue in the image. Only the densest surrounding areas of the nebula resist erosion by these stars' powerful stellar winds, forming pillars that appear to point back toward the cluster. These pillars contain forming protostars, which will eventually emerge from their dusty cocoons and take their turn shaping the nebula.

Credit: European Space Agency

Webb's Near-Infrared Spectrograph (NIRSpec) caught one very young star doing just that. Astronomers previously thought this star might be a bit older and already in the process of clearing out a bubble around itself. However, NIRSpec showed that the star was only just beginning to emerge from its pillar and still maintained an insulating cloud of dust around itself. Without Webb's high-resolution spectra at infrared wavelengths, this episode of star formation-in-action could not have been revealed.

Webb’s Near-Infrared Spectrograph (NIRSpec) reveals what is really going on in an 

intriguing region of the Tarantula Nebula. Astronomers focused the powerful instrument 

on what looked like a small bubble feature in the image from Webb’s Near-Infrared 

Camera (NIRCam). However, the spectra reveal a very different picture from a young star 

blowing a bubble in its surrounding gas. The signature of atomic hydrogen, shown in blue, 

shows up in the star itself but not immediately surrounding it. Instead, it appears outside 

the “bubble,” which spectra show is actually “filled” with molecular hydrogen (green) and 

complex hydrocarbons (red). This indicates that the bubble is actually the top of a dense 

pillar of dust and gas that is being blasted by radiation from the cluster of massive young 

stars to its lower right (see the full NIRCam image). It does not appear as pillar-like as 

some other structures in the nebula because there is not much color contrast with the 

area surrounding it. The harsh stellar wind from the massive young stars in the nebula is

 breaking apart molecules outside the pillar, but inside they are preserved, forming a

 cushy cocoon for the star. This star is still too young to be clearing out its surroundings by

 blowing bubbles – NIRSpec has captured it just beginning to emerge from the protective

 cloud from which it was formed. Without Webb’s resolution at infrared wavelengths, the 

discovery of this star birth in action would not have been possible. 

Credit: NASA, ESA, CSA, and STScI

The region takes on a different appearance when viewed in the longer infrared wavelengths detected by Webb's Mid-infrared Instrument (MIRI). The hot stars fade, and the cooler gas and dust glow. Within the stellar nursery clouds, points of light indicate embedded protostars, still gaining mass. While shorter wavelengths of light are absorbed or scattered by dust grains in the nebula, and therefore never reach Webb to be detected, longer mid-infrared wavelengths penetrate that dust, ultimately revealing a previously unseen cosmic environment.

One of the reasons the Tarantula Nebula is interesting to astronomers is that the nebula has a similar type of chemical composition as the gigantic star-forming regions observed at the universe's "cosmic noon," when the cosmos was only a few billion years old and star formation was at its peak. Star-forming regions in our Milky Way galaxy are not producing stars at the same furious rate as the Tarantula Nebula, and have a different chemical composition. This makes the Tarantula the closest (i.e., easiest to see in detail) example of what was happening in the universe as it reached its brilliant high noon. Webb will provide astronomers the opportunity to compare and contrast observations of star formation in the Tarantula Nebula with the telescope's deep observations of distant galaxies from the actual era of cosmic noon.

Despite humanity's thousands of years of stargazing, the star formation process still holds many mysteries—many of them due to our previous inability to get crisp images of what was happening behind the thick clouds of stellar nurseries. Webb has already begun revealing a universe never seen before, and is only getting started on rewriting the stellar creation story.Webb reveals cosmic cliffs, glittering landscape of star birth

Provided by European Space Agency 

NASA's Webb catches Tarantula Nebula

Tue, September 6, 2022 

A stellar nursery nicknamed the Tarantula Nebula has been captured in crisp detail by NASA's Webb telescope, revealing hitherto unseen features that deepen scientific understanding, the agency said Tuesday.

Officially known as 30 Doradus, the region of space is characterized by its dusty filaments that resemble the legs of a hairy spider, and has long been a favorite for astronomers interested in star formation.

Thousands of young stars, distant background galaxies, and the detailed structure of the nebula's gas and dust structures were viewable for the first time thanks to Webb's high resolution infrared instruments.

Webb operates primarily in the infrared spectrum, because light from objects in the distant cosmos has been stretched into this wavelength over the course of the universe's expansion.

The telescope's primary imager, Near-Infrared Camera (NIRCam), found the cavity in the center of the nebula was hollowed out by radiation carried on stellar winds emanating from a cluster of massive young stars, which appear as pale blue dots.

Webb's Near-Infrared Spectrograph (NIRSpec), which analyzes light patterns to determine the composition of objects, caught one young star in the act of shedding a cloud of dust from around itself.

The same star was previously thought to be at a later stage of formation, already well on the way to clearing its dusty bubble.

The region was also imaged using the Mid-infrared Instrument (MIRI), which uses longer wavelengths of infrared to pierce through dust grains that absorb or scatter shorter wavelengths.

This faded the hot stars and clarified the cooler regions, revealing never-before-seen points of light within the stellar nursery, which indicate protostars that are still gaining mass.

Astronomic interest in the Tarantula Nebula stems from its similar chemical composition to gigantic star-forming regions observed a few billion years after the Big Bang, a period called the "cosmic noon" when star formation peaked.

At just 161,000 light-years away, Tarantula is a readily viewable example of this flourishing period of cosmic creation.

Webb should also provide scientists the opportunity to gaze at distant galaxies from the actual era of cosmic noon, and compare it to observations of Tarantula, to understand similarities and differences.

Operational since July, Webb is the most powerful space telescope ever built, with astronomers confident it will herald a new era of discovery.

ia/mlm