Will astronomers ever be able to study exoplanet volcanoes?

Even with the best telescope images, astronomers will still be in the dark without a solid grasp of physics, especially regarding light. Interpreting scientific data from telescopic images, such as those from the James Webb Space Telescope (JWST), requires a deep understanding of these principles.

To grasp these concepts better, a bunch of physics experts focus on visualizing various scenarios using diverse telescope technologies. In a recent study, a team from UC Riverside, NASA Goddard, American University, and the University of Maryland simulated what volcanic activity might resemble on an exoplanet orbiting a Sun-like star.

So why does volcanic activity matter? In simple terms, it offers an indirect peek beneath the surface of an exoplanet to understand its geology. Essentially, volcanoes bring the planet’s internal materials to the surface, including the atmosphere. Hence, a telescope capturing an exoplanet’s volcanic activity could reveal its internal composition.

Also Read: Here’s what EU’s 5 futuristic technologies will test in space

LUVIOR telescope could change things around

At present, only a handful of telescopes have the power to spot exoplanet atmospheres—JWST being one of them. However, it can only detect them around red dwarfs. Stars akin to our Sun’s brightness would overpower the telescope’s sensors, rendering their data useless.

But things could change for upcoming telescopes. One in development is the LUVOIR telescope, currently in its early concept phase. LUVOIR, with its current specifications, might be capable of directly capturing images of Earth-sized exoplanet atmospheres around a Sun-like star at a distance of approximately 1 AU.

But what does that imply, really? Interpreting images of far-off objects demands a unique understanding. It’s not as straightforward as spotting the Eiffel Tower in a regular photograph.

It’s more about decoding data to gain a scientific comprehension of what the telescope records. One effective method is to test the telescope’s capabilities on objects we are already familiar with.

One of the extensively studied entities in the cosmos is our very own Earth. We comprehend the intricacies of our atmosphere’s spectra to a remarkable degree. Additionally, we can simulate how we expect it to appear through telescopes like LUVOIR.

Volcanoes are a great way to study a planet’s core

Although the prospect of discovering another Earth is intriguing and realistically feasible, this paper examines the “exoEarth” model in greater detail, delving into the alterations in the signal caused by various volcanic eruptions.

As previously stated, volcanoes serve as a valuable means to gain insight into a planet’s core from a distance, prompting planetary scientists to gather as much data as possible. Once again, our most comprehensive data is obtained right here on Earth.

We comprehend the chemical compositions emitted by volcanoes on our planet, which could potentially be detected in the spectral profile of an exoEarth’s atmosphere.

LUVOIR is equipped with three primary spectrographs targeting various light wavelengths: ultraviolet, visible light, and near-infrared. Simulations of an exoEarth without volcanic activity revealed that the UV wavelength exhibited heightened sensitivity to ozone, while ordinary oxygen and water vapor were more prominent in visible light. Water, by itself, was most detectable in the near-infrared band.

Also Read: Are asteroids the right place to look for the heaviest elements?

Why are volcanoes so important for the study?

Why do we care about volcanoes in all of this? Well, the aerosols emitted during eruptions can mess with the spectral readings of certain elements, especially water. As per the paper, “H20 absorption features were almost entirely concealed by volcanic aerosols while eruptions were ongoing.”

So, if LUVOIR detects a planet with a strong spectral band in the visible and NIR spectra, and these values drastically shift during the observation period, it’s a strong sign that there’s some kind of volcanic activity happening. Another clue is the existence of sulfur dioxide (which leads to acid rain) in the atmosphere of an exoplanet. This gas doesn’t last long, but it’s consistently released by active volcanoes.

Regrettably, the spectral absorption line of sulfur dioxide that LUVOIR could detect is mostly masked by a similar line for ozone, making it challenging to distinguish the presence of SO2 in the data. In general, the spectral signature of active volcanism appears to align mostly with variations in the UV (such as ozone) and visible light (like O2 and water) spectra.

So, specifically, a significant peak in the ozone spectral line might suggest the existence of an ongoing eruption. But the question remains: how likely is it that we would discover a planet like that with LUVOIR?

The chances look promising

The paper indicates a probability of approximately 90% based on the model. This percentage is contingent on the observation of 47 Earth-like planets orbiting Sun-like stars. With over 5,000 confirmed exoplanets already, the likelihood of LUVOIR discovering 47 Earth-like exoplanets appears quite promising.

It’s going to take some time before we can confirm anything. LUVOIR’s anticipated launch in 2039 means we won’t be able to gather data on exoplanet atmospheres until the 2040s.

It might seem far off, but it does provide theorists with additional time to create models of potential observations. Hopefully, there will be an abundance of new phenomena to study, not just limited to volcanoes.