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Among the first science images from the deep-space James Webb Space Telescope was an incredible Canadian feat, finding water molecules in the exoplanet WASP-96 b.
The Canadian Space Agency (CSA) funded Near-Infrared Imager and Slitless Spectrograph (NIRISS) found water molecules in the exoplanet WASP-96 b. While the planet is a large world not habitable to life as we know it, this incredible imaging feat demonstrates how we can trace the history of water in our universe using Webb.
Canada will have a front seat to this opportunity. CSA’s funding of the Honeywell-built NIRISS and Fine Guidance Sensor (FSG), which keeps the telescope pointed in the right direction, allows Canadian scientists a guaranteed share of observing time. Both of these instruments were critical to capturing the water molecules of WASP-96 b.
NIRISS, CSA explained, showed haze and clouds in the planet, which was a surprise to astronomers given that it is so hot a world and it was thought the clouds could not exist in such conditions. This may cause a rethink about how gas giant planet atmospheres are formed and evolve, which has implications for understanding the huge worlds that are close to us (like Jupiter and Saturn).
The FGS was also a requirement for the fine detail of the image, given that the sensor kept the telescope fixed on the planet as Webb orbited Lagrange Point 2. FGS will work in concert with all of Webb’s instrument, but the Canadian pair-up was a demonstration of exoplanet instrumentation in space. It builds upon decades of work from René Doyon, a noted researcher in this field at Université de Montréal who celebrated the success alongside NASA.
“One thing that is predicted to exist are water world planets that have a rocky core with thick oceans around them,” Doyon told reporters during a live streamed press conference. While it’s early days yet for WASP-96 b, he noted that Webb did successfully “detect the water features in the atmosphere” that could be associated with such water worlds.
Webb’s investigation team chose this planet due to a combination of circumstances that would make it shine well in infrared light. It is close to its parent star, and therefore highly heated. It has a “puffy” atmosphere, which means the planet will show up well at a distance. The large planetary size and lack of stray light interfering with observations also worked in Webb’s favour.
“The exoplanet, it was picked because we knew it would have strong features so that we had high chance of detecting them,” said Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute in Baltimore, which manages the telescope’s schedule, in the same press conference.
With more than 5,000 planets detected to date, Webb will finally be able to bring these little worlds into closer view. If the newly imaged exoplanet is indeed a “water world,” there are advantages to Webb’s spectrum that will make it truly able to seek out similar ones to assess their role in spreading water throughout the universe.
NIRISS, NASA noted in an explainer about the WASP-96 b discovery, caught a span of infrared wavelengths previously inaccessible in other observations – specifically, those longer than 1.6 microns. This is crucial as that set of wavelengths best captures the spectrum of water and life-friendly elements like oxygen, methane and carbon dioxide.
In other words, investigators during the press conference said Webb will go a long way to figuring out whether Earth is unique as a habitable planet – and whether habitable planets, if they exist, are much more common among red dwarf stars. (Our observations to date have been somewhat biased as smaller stars give off less light and are therefore easier for planet detections, but Webb and forthcoming observatories are more powerful than past generations.)
“There’s many, many new discoveries that we can expect,” added Doyon, who is the principal investigator of NIRISS. As Doyon helms this powerful instrument, we can expect other Canadian investigations of exoplanets in the coming months under Cycle 1 – the first cycle of Webb observations.
Two Ph.D. students – McGill University’s Lisa Dang and Montréal’s Olivia Lim – each are helming proposals on rocky exoplanets. Dang will look at a lava world, K2-141, and collect information on the scorching surface temperature (thousands of degrees Celsius) using Webb’s Mid-Infrared Instrument.
Lim will look at other rocky worlds that form a part of the famous TRAPPIST-1 system, which includes a selection of planets that might be in the habitable zone of the red dwarf star. That team will use NIRISS in addition to the Near Infrared Spectrograph (NIRSpec).
Hot Jupiters will come under scrutiny in two other Canadian investigations. Stefan Pelletier (Université de Montréal, Ph.D. student) will study the formation scenario of WASP-127 b using NIRSpec, while James Sikora (Bishop’s University, postdoctoral research) will seek clouds in a hot Jupiter known as HD80606 b using NIRSpec.
Brown dwarfs, intriguing objects somewhere between a star and a planet, will be investigated with Loïc Albert (Université de Montréal and a Webb instrument scientist). The goal is to image very small cold brown dwarfs, called Y dwarfs, using NIRCam (Near Infrared Camera).
All of these will build upon decades of work by Canadian researchers in seeking out exoplanets, notably including a 2008 “Scientist of the Year” honour by Radio-Canada that included Doyon and two other Canadian researchers. The team successfully imaged three Jupiter-scale planets orbiting a star known as HR 8799 in a unique feat of that era.
The imaging work back then formed a valuable basis for all the new investigations that will be using Webb in the coming months and years. The telescope will also be tasked with seeking out unseen worlds along with verifying the metrics of older ones, and will be operational for the next 20 years. As the Hubble Space Telescope was crucial to charting our expanding universe, Webb will serve as a space characterizer of exoplanets in ways we cannot yet imagine.
