From Webb: “Birth of Stars & Protoplanetary Systems”

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James Webb Space Telescope

The Pillars of Creation in the Eagle Nebula captured in visible light by Hubble. Stellar nurseries are hidden within the towers of dust and gas. Credit: NASA/ESA/Hubble Heritage Team (STScI/AURA)/J. Hester, P. Scowen (Arizona State U.)

Inside the Pillars of Creation

While this image is spectacular, there are actually stars that Hubble can’t see inside those pillars of dust. And that’s because the visible light emitted by those stars is being obscured by the dust. But what if we used a telescope sensitive to infrared light to look at this nebula?

The next image is another Hubble view, but this time in near-infrared. In the infrared more structure within the dust clouds is revealed and hidden stars have now become apparent. (And if Hubble, which is optimized for visible light, can capture a near-infrared image like this, imagine what JWST, which is optimized for near-infrared and 100x more powerful than Hubble, will do!)

Another nebula, the “Mystic Mountains” of the Carina Nebula, shown in two Hubble images, one in visible light (left) and one in infrared (right).
In the infrared image, we can see more stars that just weren’t visible before. Why is this?

The Pillars of Creation in the Eagle Nebula captured in infrared light by Hubble. The light from young stars being formed pierce the clouds of dust and gas in the infrared. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Comparison of the Carina Nebula in visible light (left) and infrared (left), both images by Hubble. Credit: NASA/ESA/M. Livio & Hubble 20th Anniversary Team (STScI)

How Do Infrared Cameras Work?

We can try a thought experiment. What if you were to put your arm into a garbage bag? Your arm is hidden. Invisible.

But what if you looked at your arm and the garbage bag with an infrared camera? Remember that infrared light is essentially heat. And that while your eyes may not be able to pick up the warmth of your arm underneath the cooler plastic of the bag, an infrared camera can. An infrared camera can see right through the bag!


ALMA image of the young star HL Tau and its protoplanetary disk. This best image ever of planet formation reveals multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas. Credit: ALMA (NRAO/ESO/NAOJ); C. Brogan, B. Saxton (NRAO/AUI/NSF)

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

The Dusty Cocoons of Star and Planet Formation

JWST’s amazing imaging and spectroscopy capabilities will allow us to study stars as they are forming in their dusty cocoons. Additionally, it will be able to image disks of heated material around these young stars, which can indicate the beginnings of planetary systems, and study organic molecules that are important for life to develop.

Key Questions

JWST will address several key questions to help us unravel the story of the star and planet formation:

How do clouds of gas and dust collapse to form stars?
Why do most stars form in groups?
Exactly how do planetary systems form?
How do stars evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets?

Infrared Spitzer image of a star-forming region. Credit: NASA/JPL-Caltech/ Harvard-Smithsonian CfA

NASA/Spitzer Telescope

JWST’s Role in Answering These Questions

To unravel the birth and early evolution of stars and planets, we need to be able to peer into the hearts of dense and dusty cloud cores where star formation begins. These regions cannot be observed at visible light wavelengths as the dust would make such regions opaque and must be observed at infrared wavelengths.

Stars, like our Sun, can be thought of as “basic particles” of the Universe, just as atoms are “basic particles” of matter. Groups of stars make up galaxies, while planets and ultimately life arise around stars. Although stars have been the main topic of astronomy for thousands of years, we have begun to understand them in detail only in recent times through the advent of powerful telescopes and computers.

A hundred years ago, scientists did not know that stars are powered by nuclear fusion, and 50 years ago they did not know that stars are continually forming in the Universe. Researchers still do not know the details of how clouds of gas and dust collapse to form stars, or why most stars form in groups, or exactly how planetary systems form. Young stars within a star-forming region interact with each other in complex ways. The details of how they evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets remains to be determined through a combination of observation and theory.

The stages of solar system formation. Credit: Shu et al. 1987

The stages of solar system formation are illustrated to the right: starting with a protostar embedded in a gas cloud (upper left of diagram), to an early star with a circumstellar disk (upper right), to a star surrounded by small “planetesimals” which are starting to clump together (lower left) to a solar system like ours today.

The continual discovery of new and unusual planetary systems has made scientists re-think their ideas and theories about how planets are formed. Scientists realize that to get a better understanding of how planets form, they need to have more observations of planets around young stars, and more observations of leftover debris around stars, which can come together and form planets.


Related Content
More Comparison Images

Here’s is another stunning comparison of visible versus infrared light views of the same object – the gorgeous Horsehead Nebula:

The Horsehead Nebula in visible light, captured by the Canada-France Hawaii Telescope. Credit: NASA

Visible Light Horsehead Nebula

CFHT Telescope, Maunakea, Hawaii, USA

Infrared Light Horsehead Nebula

The Horsehead Nebula in infrared light, captured by the Hubble Space Telescope. Credit: NASA/Space Telescope Science Institute (STScI)

NASA/ESA Hubble Telescope

Related Video

This video shows how JWST will peer inside dusty knots where the youngest stars and planets are forming.

See the full article here .

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The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

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