Next generation telescopes can detect signs of life on habitable planets

A team of astronomers led by the Ohio State University (OSU) has found that with the development of next generation telescopes, scientists could observe weather phenomena on distant exoplanets, and thus shed new light on the possibility of extraterrestrial life.

High-powered astronomical observatories such as the Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT) will be the largest ground-based telescopes ever constructed and will likely exceed the capabilities of the James Webb Space Telescope (JWST).

“Learning about the atmospheres of other objects outside our solar system not only informs us how Earth’s atmosphere may behave but allows scientists to scale those concepts to study potentially habitable planets,” explained lead author Michael Plummer, a graduate student in Astronomy at OSU.

Measuring cosmic objects 

According to the researchers, data collected with these next generation telescopes will allow astronomers to use Doppler imaging – a groundbreaking technique that can recreate 2D maps of an object’s surface – to accurately measure the magnetism and chemistry of ultracool cosmic objects with temperatures below 2700 K. This category includes brown dwarfs (BDs), very low-mass stars (VLMs), or even some exoplanets.

Since the existence of magnetic fields is necessary to support life on a planet, particularly in smaller star systems, the ability to detect their presence is crucial for assessing whether a planet could be habitable or not. 

To simulate and infer the presence of surface discrepancies such as magnetic star spots, cloud systems, and other atmospheric phenomena like hurricanes, the experts previously developed a publicly available analytical code named “Imber.”

Capabilities of next generation telescopes 

In the current study, the experts used this technique to estimate the scientific capabilities of various ELTs’ instruments – the GMT’s Consortium Large Earth Finder (GMT/GCLEF), the ELT’s Mid-Infrared ELT Imager and Spectrograph (ELT/METIS) and the TMT’s Multi-Objective Diffraction-limited High-Resolution Infrared Spectrograph (MODHIS) – to detect surface variations on six cosmic objects. 

These objects included the star of Trappist-1, a well-known seven-planet system located approximately 40 light-years from Earth, two brown dwarfs, and three exoplanets. 

What the researchers learned 

The analysis revealed that, although discerning star spots on Trappist-1 was difficult for all three instruments due to its edge-on inclination (i.e. the fact that its orbit is parallel to the rest of the sky), both next generation telescopes ELT and TMT could provide high-resolution observations of the brown dwarfs and exoplanets during a single rotation.

By contrast, GMT’s instruments required multiple rounds of observations to identify surface irregularities on the exoplanets.

According to Plummer, their technique already garnered interest from astronomers aiming to identify or confirm planetary bodies using the radial velocity method, a way of discovering exoplanets by identifying the slight gravitational effect cosmic objects have on the stars they orbit.

“The more we learn about other similar planets to Earth, the more those discoveries should inform Earth science itself. Our work is particularly well-suited to help make those real-world observations,” Plummer concluded.

The study is published in the Astrophysical Journal.

More about habitable planets

Many exoplanets are located in what scientists refer to as the “habitable zone” or “Goldilocks zone” around their host stars. This is the region around a star where conditions might be just right – not too hot and not too cold – for liquid water to exist on the surface of a planet, which is a key ingredient for life as we know it.

Some of the most notable potentially habitable exoplanets include:

Proxima Centauri b

This exoplanet orbits the star Proxima Centauri, which is the closest star to our sun at approximately 4.24 light years away. Proxima Centauri b is located within the habitable zone of its star and may have conditions suitable for liquid water. However, the star it orbits is a red dwarf, which are known to produce harsh solar flares that could hinder life.

Kepler-22b

This was the first exoplanet discovered by the Kepler Space Telescope that was located within the habitable zone of its star. Kepler-22b is about 2.4 times the size of Earth and orbits a star similar to our own, although slightly cooler.

Teegarden’s Star b and c

These two exoplanets orbit Teegarden’s Star, a red dwarf only 12 light-years away from us. They’re both near-Earth size and are located within their star’s habitable zone.

TRAPPIST-1 system

This is one of the most exciting discoveries, as this system contains seven Earth-sized planets, at least three of which are located in the habitable zone of the star. TRAPPIST-1 is a red dwarf star located about 40 light-years away.

It’s important to remember that being within the habitable zone doesn’t guarantee a planet is actually habitable. Many other factors, such as the planet’s atmosphere, magnetic field, geology, and more, also play a crucial role in its potential habitability.

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By Andrei Ionescu, Earth.com Staff Writer

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