‘Webb telescope will certainly search for Earth-like planets’: Project scientist

Webb’s carries four major scientific instruments: Near-Infrared Camera (NIRCam); Near-Infrared Spectrograph (NIRSpec); Mid-Infrared Instrument (MIRI); Near-Infrared Imager; and Slitless Spectrograph (NIRISS) with the Fine Guidance Sensor (FGS).

These will help find clues about the first formed galaxies, the evolution of our solar system and also search for exoplanets and building blocks of life elsewhere in the universe.

In an interview with indianexpress.com, Dr. Knicole Colón, James Webb Space Telescope Deputy Project Scientist for Exoplanet Science, explains how the mission will study exoplanets and their atmospheres.

How will NIRISS look for exoplanets?

The three main components of NIRISS are cameras, spectrographs and an instrument called the Aperture Masking Interferometer or AMI.

So a camera, as you imagine, like on your phone, you take a picture and it’s just a direct image. But with the spectrographs, there are different types of absorbing modes where you can see a star not just as a dot. What you’re doing is you’re taking the light from the star and the spectrograph spreads the light from that star out. So instead of seeing it just as a white or yellow dot, it spreads it out into different increments of light. Somewhat like a prism, it splits the light up so that you can measure and look at specific wavelengths.

The aperture mask is a very special mode as well. Instead of taking a direct picture, you remove or block the light from a star, so that you can look for the faint dots around it that could be an exoplanet.

Why do we need an infrared camera to find exoplanets?

Infrared cameras will help capture things we cannot see with our eyes. Beyond our visual range, there are thermal signatures that are emitted by warm stars. In our search for exoplanets, there are two ways in which infrared helps.

One, if we want to take direct pictures of exoplanets, it’s actually easiest to look in the infrared, because the planets are usually very warm from having recently formed. And so the young planets are the brightest in the infrared compared to their star.

The other aspect is when we’re just looking at planets that may be in transit or passing in front of their star, we can look at their atmosphere. The infrared is beneficial because that’s where water, carbon dioxide, methane, and other major molecules have the strongest absorption features that we could look for.

Your area of research is “extreme” exoplanets. Will Webb be looking for such exoplanets?

For me, ‘extreme’ is something that’s just not seen in our solar system. For example, planets that have orbits of less than a day or extremely hot ones – some of them hotter than their stars — or those with really crazy orbits.

Some exoplanets have orbits like comets – they orbit really far from their star, but they come back and are really close to their star. So the planet when it comes closest to the star gets rapidly heated up by the star, all of a sudden after being cold for a while. There are interesting dynamics that could happen in the atmosphere.

And yes, Webb will be observing some of these extremely hot systems and those with very non-circular orbits and provide new insights into: What does it mean to be extreme? What is happening in that atmosphere? Do they have weather patterns and clouds? And we can relate that back to our own solar system.

Studying these extreme exoplanets will help answer questions like: How did our solar system end up with eight major planets at these distances from the Sun? Is there a limit to when planets can’t form? A lot of big questions which all tie back to our knowledge of how the universe works. It is like finding and filling new puzzle pieces.

So, will Webb search for habitable exoplanets? Can we finally find alien life?

With every telescope, we are launching and every study we’re doing — at least my intention — is to get closer to searching for planets and studying planets that are potentially like Earth – maybe the same size or the same temperature.

And Webb will certainly look at some of these Earth-like planets. But it is really hard to look for signs of life. I don’t expect it will actually find signs of life because it is going to require a lot of data. Even if we could find some evidence, it’ll be a long time before we confirm.

Maybe future telescopes or the next generation of telescopes will find something interesting.