NASA James Webb Target Acquired: A Super-Earth Covered in Lava Oceans
The new James Webb Space Telescope is nearing completion, and NASA recently revealed some potential discovery targets for the multibillion-dollar machine.
Why it matters
This space-based telescope will provide scientists with unprecedented views of distant objects, providing new data and images that will reshape our understanding of the universe.
It’s getting closer to showtime for NASA’s cutting-edge mission to unveil an unfiltered universe and redefine the whimsy of “looking up at the stars.” The James Webb Space Telescope is just “weeks away” from full operation, according to NASA, after a successful journey that included traveling a million miles from Earth and aligning its 18 hexagonal, gold-plated mirrors.
NASA is making a list of exciting interstellar targets in preparation for Webb’s first cosmic discoveries. On Thursday, it announced two that will not disappoint: a pair of scorching super-Earths that sound eerily similar to Star Trek worlds.
One is covered in lava oceans, while the other does not have an atmosphere.
“They will give us fantastic new perspectives on Earth-like planets in general, helping us learn what the early Earth might have been like when it was hot like these planets are today,” Max Planck Institute for Astronomy’s Laura Kreidberg said in a statement.
Exoplanet muse No. 1
First up is exoplanet 55 Cancri e, also known as a super-hot super-Earth according to NASA. This rocky orb is about 40 light-years away from us (one light-year equals the distance light travels in one year) and 8.63 times the mass of our planet.
55 Cancri e orbits a sunlike star, similar to the unbreakable bond between the Earth and the sun, but it’s extremely hot because it’s only 1.5 million miles away. Extremely hot. For context, the Earth orbits the sun at a distance of approximately 95 million miles. That is why scientists believe the rocks on 55 Cancri e are literally melting into lava oceans. This isn’t even the strangest part.
The proximity of this ultra-hot planet to its “sun” also leads to a major mystery, which Webb is well-equipped to solve.
“Planets that orbit this close to their star are assumed to be tidally locked,” NASA explained, which means that one side of the planet must always face the star. Intuitively, scientists believe that such a tidal lock would make the star-facing side of the planet much hotter than the other, and that this heat level should not fluctuate significantly. But… 55 Cancri e does not appear to have these characteristics.
However, “55 Cancri e could have a thick atmosphere dominated by oxygen or nitrogen,” said Renyu Hu of NASA’s Jet Propulsion Laboratory in Southern California in a statement. Alternatively, Alexis Brandeker, a Stockholm University researcher who leads another team studying 55 Cancri e, suggests that we may have been mistaken about 55 Cancri e’s tidal lock in the first place.
“That could explain why the hottest part of the planet is shifted,” Brandeker said. “Just like on Earth, it would take time for the surface to heat up. The hottest time of the day would be in the afternoon, not right at noon.” If Brandeker is right, it’s also pretty likely that 55 Cancri e isn’t only home to lava oceans, but also to lava rain.
On the one hand, Hu and his colleagues are determined to get to the bottom of this by using the day side of the planet to train Webb’s groundbreaking near-infrared camera (NIRCam) and mid-infrared instrument (MIRI). Both technologies use infrared imaging to see what the human eye cannot.
Light from the infrared region of the electromagnetic spectrum is essentially invisible to us, but these instruments can detect photons from deep space and translate them into signals that we can understand. “If it has an atmosphere, [Webb] has the sensitivity and wavelength range to detect it and determine what it is made of,” Hu said of 55 Cancri e.
Brandeker and colleagues, on the other hand, intend to use NIRCam to measure the heat emitted from the lit side of 55 Cancri e during four different orbits.
Exoplanet muse No. 2
Another very hot, albeit technically cooler, extrasolar planet called LHS 3844 b is located a little further away from us than 55 Cancri e, at a distance of 48 light-years. This one is about 2.25 times the mass of Earth and orbits the red dwarf star LHS 3844. The planet’s major draw is that it doesn’t appear to have… any air?
According to NASA, it lacks a “substantial atmosphere.”
Webb can decode the secrets of this planet by using its powerful infrared spectroscopy mechanisms. Due to the lack of atmosphere, NIRCam may not work in this case, but MIRI may. MIRI cannot precisely “image” LHS 3844 b, but it can detect the presence of various rock compositions, such as granite or basalt, and possibly even volcanic gas if the planet is volcanically active.
“It turns out that different types of rock have different spectra,” Kreidberg said. “You can see with your eyes that granite is lighter in color than basalt. There are similar differences in the infrared light that rocks give off.”
While these two exoplanets are truly amazing Webb science targets, they only scratch the surface of what this telescope has the potential to do for astronomy in the coming years. Researchers from around the world have already added to Webb’s arsenal informally, with one team identifying extraterrestrial biosignatures and another team focusing on a supermassive black hole ancestor.
This high-tech, multibillion-dollar telescope could solve the mystery of why Neptune is strangely cooling, and it could even provide us with a beautiful, gleaming view of Earendel, the farthest star ever seen by humans.
Time will only tell. Webb, the ball is in your court.