Astronomers working with the James Webb Space Telescope are revelling in the orbiting observatory’s first-ever images of the Orion Nebula – a glowing cauldron of gas and dust where stars and planets are in the process of being born.
The nebula, a familiar object to backyard stargazers, is about 1,350 light years away, making it the nearest major star-forming region to Earth and a natural laboratory for understanding the origins of solar systems, including our own.
“I don’t think we had imagined such spectacular images,” said Els Peeters, an astronomer at Western University in London, Ont., and one of three co-leaders of the effort to study the Orion Nebula using Webb, of the pictures released Monday. “They are absolutely mind-blowing.”
The project, involving more than 100 researchers in 18 countries, was selected as one of the first “early science” priorities for the newly commissioned space telescope, a NASA-led observatory that includes Canada as a partner and began returning data in July. However, the shifting position of the sun in relation to Orion meant the telescope could not be safely pointed at the nebula until this past weekend, when Dr. Peeters and her colleagues made their observations.
The results show a portion of the nebula know as the “Orion bar” in sharp and colourful detail as it cuts diagonally across the telescope’s field of view.
The bar is a region of higher density gas that has been swept up by the pressure of intense ultraviolet radiation emanating from a quartet of bright stars located just outside of the frame of the image to the upper right. Like the snow piled in front of a snowplow, the bar is the leading edge of a bubble of interstellar material that the four stars have created inside the heart of the nebula.
The bar is an important structure, in part because the higher density of material helps to shield colder, more complex molecules that form in the nebula, including hydrocarbons and microscopic dust grains that are the seeds of future planets.
In addition to the images, Dr. Peeters said she and her colleagues used the telescope to acquire spectroscopic data, which provides information about the chemical composition of the nebula.
For astronomers, the nebula offers a chance to study how interstellar material coalesces and evolves in a high radiation environment. Because of its close proximity, it also acts like a Rosetta stone that can help clarify what is taking place in more distant star-forming regions in our own galaxy and beyond, and at smaller scales when applied to the birth of individual stars.
“I think these images and data will be used for decades,” Dr. Peeters said.
Orion was explored by the Hubble Space Telescope in the 1990s and there are many similarities in what the two instruments reveal. However, Webb, which is sensitive to infrared wavelengths of light, offers a different and complementary perspective. For example, the dust that appears in silhouette or is seen only through reflected light in Hubble’s view glows warmly when observed by Webb.
The difference can yield previously unseen detail about how the nebula has been shaped by its chaotic environment. Similar leaps in understanding have followed every improvement in the observation of the nebula since it was first studied and sketched by Dutch astronomer Christiaan Huygens in 1659.
“Orion has never disappointed,” said C. Robert O’Dell, an astronomer at Vanderbilt University in Tennessee, who was not involved with the Webb images but led Hubble’s observing campaign of the nebula nearly three decades ago. “It’s always one of the first targets and it always seems to give us something new.”
Webb was launched in December and fully commissioned earlier this year. Since then it has yielded a steady stream of new images and findings, from distant galaxies to direct images of planets orbiting other stars.
“We’re basically getting one fantastic image after another – we’re so spoiled at this point,” Dr. Peeters said. “It’s really just a joy to be part of that.”