James Webb reveals the stunning beauty of an extremely young proto-star

A newborn protostar discovered in 2012 reveals its details thanks to James Webb’s stunning shot.

On the surface, it looks like a kind of cosmic hourglass. Instead of sand, it looks like interstellar gas patiently flowing from a tiny point of light. It is an illusion: it is not an instrument for measuring time. This picture shows the formation of a star. A star in the making. A protostar. Her name ? L1527.

This photo was released by NASA on Nov. 16 — a busy day with the long-awaited first flight of the Space Launch System (SLS), marking the official launch of the Artemis program and the return of astronauts to the Moon. It was captured by the James Webb Space Telescope with its NIRCam infrared camera.

The center of this hourglass is as wide as the Solar System. // Source: NASA, ESA, CSA and STScI

A pregnant star in the center of the hourglass. If we look carefully, we notice that the star appears to be crossed by a horizontal black line. This dark line is not a feature of a proto-star, but a sign of another birth: a proto-planet. It is actually part of the disk of matter that formed around the star.

A protostar only 100,000 years old

It is even a very young protostar – its age is estimated to be about 100,000 years (and very young on the scale of the Universe). In the classification of proto-stars, it falls into the so-called class 0, the earliest stage of star formation. This classification is based on observations of the star’s brightness, as well as the “chaos” around it.

Gas is everywhere, including the dark parts around L1527. The more red and orange the color, the higher the density of the dust. But as the chromatic range moves toward blue, the powder becomes finer and more spaced. Admiring the change of colors, we guess this: the distribution is not homogeneous enough.

Then an obvious question arises: why does the star not shine everywhere, including dark places?

It is due to the disk of matter that has the masking effect and blocks the star’s light. As a result, the gas is illuminated only where the disc does not obstruct, i.e. “up” and “down”. It’s a bit like a flashlight: the light cone goes only in one direction (others are “blocked” by the body and components of the device).

A solar flare on October 28, 2021, as seen by SDO.  // Source: NASA/GSFC/SDO
The Sun is a fully formed star. This is what L1527 will look like one day. // Source: NASA/GSFC/SDO

And this protoplanetary disk is not small. The American space agency shows that it has the size of our solar system, which is tens of billions of kilometers long. But from where you are, everything looks infinitely smaller: L1527 is about 450 light-years from Earth in the constellation Taurus.

Despite the great distance that separates us from the star, astronomers can say that L1527, discovered in 2012 ” it still does not produce its own energy by nuclear fusion of hydrogen », like an ordinary star. Its shape is not completely spherical, but also ” unstable “. As for its mass, it is between 20-40% of the mass of the Sun.

This mass growth is fully underway – the surrounding gas clusters show it. All the surrounding stardust is gradually drawn towards the center where the first star is. This feeds the star, allowing it to grow, compress, and reach the equilibrium limit between its gravitational mass and the initiation of nuclear fusion.

This is a phase that will be very long on our scale. L1527 will not become a star in its own right for tens to hundreds of thousands of years. But for astronomers, it’s a great opportunity to have a situation that can tell us about the formation of stars, planets, and solar systems. Like ours.

To continue

Distant galaxies as seen by James Webb.  // Source: NASA, ESA, CSA, Tommaso Treu (UCLA)

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