Cosmic hourglass: Webb captured an image of a protostar shrouded in dark clouds

Cosmic hourglass: Webb captured an image of a protostar shrouded in dark clouds

The protostar L1527 is embedded in a cloud of material that fuels its growth.

Just last month, the James Webb Telescope gift us a spectacular new image of Pillars of creation— perhaps the most famous image made by Webb’s predecessor, the Hubble Space Telescopein 1995. Now the telescope is giving astronomers clues about the formation of a new star, p stunning image of a dark hourglass-shaped cloud surrounding a protostar, an object known as L1527.

As do we reported earlierthe James Webb Space Telescope launched in December 2021 and after a hectic deployment of solar shields and mirrors for several months, began capturing stunning images. First, there was deep field image of the Universe, released in July. This was followed by images of atmospheres of exoplanetsthe Southern Ring Nebula, a cluster of interacting galaxies called the Stefan Quintet, and the Carina Nebula, a star-forming region about 7,600 light-years away.

In August we received wonderful images of Jupiter, including the auroras at both poles, which are the result of Jupiter’s powerful magnetic field, as well as its thin rings and two of the gas giant’s small moons. This was followed a month later by mosaic image showing a panorama of star formation stretching across an astonishing 340 light-years in the Tarantula Nebula – so named for its long dusty filaments. We were also treated to spectacular images of Neptune and his ringswhich have not been observed directly since Voyager 2 flew by the planet in 1989, and as already mentioned, the Pillars of Creation.

This last image is courtesy of Webb’s primary photographer, the Near infrared camera (MIRCam). To capture images of very faint objects, the NIRCam coronagraphs block out any light coming from brighter objects nearby, similar to how shielding our eyes from bright sunlight helps us focus on the scene in front of us. L1527’s dark clouds are only visible in the infrared spectrum, and NIRCam was able to pick up features that were previously hidden from view. Look at this:

Zoom in / The material ejected from the star has cleared cavities above and below it, whose borders glow orange and blue in this infrared view.


Back in 2012, astronomers used Submillimeter array— a collection of eight radio telescopes arranged in an interferometer that is also part of the Event Horizon telescope — for study the accretion disk around L1527 and measure its properties, including rotation. They found that the disk showed a Keplerian motion similar to the planets in our solar system, which allowed them to determine the mass of the protostar. So learning more about L1527 can teach us more about what our own Sun and solar system were like in their infancy.

Protostars are the earliest stage of stellar evolution, typically lasting about 500,000 years. The process begins when a fragment of a molecular cloud of dense dust and gas acquires enough mass from the surrounding cloud to collapse under its own gravity, forming a pressure-supported core. The nascent protostar continues to attract mass to itself and the infalling material spirals around the center to create an accretion disk.

The protostar within L1527 is only 100,000 years old and therefore does not generate its own energy from nuclear fusion, which turns hydrogen into helium, like a full star. Rather, its energy comes from radiation released by shock waves on the surface of the protostar and its accretion disk. Right now, it’s basically a spherical puffy lump of gas between 20-40 percent of the mass of our Sun. As the protostar continues to gain mass and compress further, its core will continue to heat up. Eventually, it will become hot enough to cause nuclear fusion and a star will be born.

The Webb image above shows how material ejected from L1527’s protostar has created empty cavities above and below; the glowing orange and blue regions represent the boundaries delineating these regions. (The color of the blue region is because there is less dust than the orange regions above it, which trap more blue light in the dense dust so that it cannot escape.) The accretion disk appears as a dark bar. Also in the image are strands of molecular hydrogen, the result of impacts from the ejecta material of the protostar.

Listed image by NASA/ESA/CSA/STScI/J. De Pasquale

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