Astronomy | Welcome to the new era

The historic unveiling of four space telescope images James Webb, Tuesday, made it possible to note the power of the device located 1.5 million kilometers from the Earth. New celestial bodies became visible for the first time.

Mathieu Perreault
The Press

water and clouds

A Canadian instrument on Webb detected water on an exoplanet, called WASP-96b, located 1150 light years away. “We knew there was water, but it’s an independent confirmation,” explains Nathalie Ouellette, scientist in charge of communications for the James Webb in Canada. “But we didn’t manage to see any clouds, which was unusual. With the Webb, we could see the clouds of water vapour. With Hubble, there was a lot of noise in the data. This is a planet the size of Jupiter whose orbit around its star, which is comparable in size to that of our Sun, lasts only a few days. The presence of water and clouds was revealed on a graph by the light that passed through WASP-96b when it was between its star and the Webb.

Mysterious structures

The constellation Carina, located 7600 light-years away, is a nebula, a cloud — in this case a nursery of stars. “We saw structures that we didn’t know existed,” said Ms.^me Ouellette, who is also coordinator of the Institute for Research on Exoplanets at the University of Montreal (iREx). “These are bubbles formed by the birth of stars, when surrounding dust and gas are pushed outwards. We don’t really understand the strange shapes we see. Hundreds of new stars also became visible.

galaxy collisions

Stephan’s Quintet is a collision zone between five galaxies, 290 million light-years away. “We saw a hypermassive black hole that we knew existed, but we hadn’t seen the jets of dust and gas,” says Ms.^me Ouellette.

A second star

The Southern Ring Nebula, located 2000 light-years away, is more of a binary system of two stars at the end of their life. She revealed to Webb its second star, whose presence was known, but which had never been observed.

13.1 billion years old

Monday evening President Joe Biden “scooped” NASA by unveiling one of the first five images of the Webb. It is a cluster of galaxies called SMACS 2073, located 4.6 billion light-years from Earth. In the image, we see galaxies even further away, located up to 13.1 billion light-years away. “These are the lines on the image, specifies M^me Ouellette. This is created by the distortion of SMACS 2073. SMACS 2073 is so massive that light from objects behind it is bent. This “lensing effect” makes it possible to observe even more distant regions, witnesses of the beginning of the Universe. As the Universe is expanding, the further away an object is from Earth, the longer it takes for the light it emits to reach us. Thus, when we look at an object located 1 light year from Earth, we see it as it was a year ago, because the light took a year to reach us, for example. the Webb should be able to observe the first galaxies, which formed 13.2 to 13.6 billion years ago. Why not have already shown these first galaxies? “We only used a dozen hours to have the galaxy 13.1 billion light years away, says M^me Ouellette. It would have taken a week or two with Hubble, if it had been possible. We demonstrate the capabilities of Webb. »

Two Canadian instruments

The discovery of water and clouds on WASP-96b was made by a “Near Infrared Imager and Slitless Spectrometer” (or NIRISS, for the acronym), developed at the University of Montreal. The NIRISS will notably do “slitless spectroscopy”, which is less precise in terms of resolution, but allows the analysis of many more objects at the same time. Canada is also responsible for the “Fine Guidance Sensor” (FGS) which will help point the Webb when he goes to make his observations.