by It could be argued that the search for habitability elsewhere around the globe can be reduced to the search for water. We have not yet discovered life forms that separate this substance from our own concept of “life”, so we have no choice but to accept the cosmic water trail as our north star as we seek to find life that mirrors ours. own.
It is for this reason that scientists jump for joy when they discover that an exoplanet is likely to hold any water at all – but especially liquid water, rather than ice or water vapor. And I’d expect that at least one astronomer has been jumping up and down somewhere recently, and a team of researchers has just announced that there’s a fun planet beyond Solar system a temperate ocean of water could be about half the size of the Atlantic. Even better, the find thanks to the James Webb Space Telescope.
“Of all the currently known temperate exoplanets, LHS 1140 may be our best bet to one day indirectly confirm liquid water on the surface of an alien world outside our solar system,” Charles Cadieux, lead author of a paper on the discovery and her doctoral student at the University of Montreal, said in a statement. “This would be a major milestone in the search for habitable exoplanets.”
LHS 1140 b was given, the exoplanet orbits a red ox star about a fifth the size the sun and sits 48 light year away from World in the constellation Cetus which translates, as luck would have it, to “the whale.” But the most important thing about LHS 1140 b is that it resides in the star’s habitable zone, otherwise known as the “Goldilocks zone”. As that nickname would suggest, this is the area around a star that is neither too hot nor too cold to host a liquid water world, but fits the standard in which the fairytale character Goldilocks lives. . The world also has a second major victory.
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“This is the first time we’ve ever seen a hint of an atmosphere on a habitable zone rocky or ice-rich exoplanet,” Ryan MacDonald, a NASA Sagan Fellow in the University of Michigan Department of Astronomy, who helped with the analysis of LHS 1140 b’s atmosphere, said in the statement. Per Macdonald, the team could even find evidence of “air” on it.
On the first part of that statement, however, you may notice that MacDonald suggests that the exoplanet may be rocky or icy. This brings us to some backstory.
LHS 1140 b lore
Although it’s making headlines now because of the new study involving JWST data, LHS 1140 b has been on the radar of planet hunters for some time. In fact, experts have already theorized that this could have been a water world in the past, and even have some similar views on how it could offer the first ever direct evidence to mankind. exoplanetary liquid water. None of that is new. Cadieux himself has tackled the world’s promise before, and an army of telescopes have investigated it in detail, including the now retired Spitzer telescope, the Hubble Space Telescope and the Transiting Exoplanet Survey Satellite (TSES).
However, something has been missing until now: the keen eye of the James Webb Space Telescope.
It was necessary because, for a long time, there had been something of a gap in the literature about LHS 1140 b. Basically, the problem was that scientists couldn’t fully confirm whether the exoplanet was a mini-Neptune – a planet less massive than our parent planet. Neptune, but one that still has Neptunian characteristics – or Super Earth. A superworld is a world that is larger than Earth, but is still rocky or rich in water. The latter usually sounds the “possible habitable” alarm, and the JWST, scientists imagined, could be the one to set it off.
This seems like an accurate conclusion. As the team’s statement on the study shows, their work not only strongly excluded “the mini-Neptune scenario”, but also confirmed that the world could have a nitrogen-laced atmosphere like Earth does. “Although only a temporary result, the presence of a nitrogen-rich atmosphere would indicate that the planet has retained a substantial atmosphere, creating conditions that could support liquid water,” he says.
It is worth noting that LHS 1140 b is not entirely alone in its disturbing characteristics; there are also a variety of other habitable exoplanets to which scientists are drawn. Probably the most obvious are the seven lives of the TRAPPIST-1 system, a planetary system that looks disturbingly similar to the structure of our solar system. The septate of orbits is similar to our octet (hello, Pluto) and some of them are in the habitable zone like Earth.
However, the search for habitability in TRAPPIST-1 has recently been complicated by a very interesting JWST study. It showed that the anchor star of the system is extremely active so that it could skewed our perceptions, leading us to believe that a world in the system is habitable when in fact it is not. Even the JWST has limitations. So, to that end, LHS 1140 b has some special decorations.
“The star LHS 1140 appears to be quieter and less active,” Macdonald asserted, “which makes it much less challenging to disentangle the atmosphere of LHS 1140 from stellar signals caused by starspots.”
Brace yourself for even more specs
The excitement about LHS 1140 b is contagious. There is so much to say about it.
For example, the JWST data also suggests that the exoplanet’s mass could be made up of between 10 percent and 20 percent liquid water—and, it paints a fascinating picture of what the planet would look like in simple terms . It may look like a snowball, essentially, that orbits its star as it rotates so that one side always faces that star. It’s kind of like the moon’s orbit around the Earth; we can never see beyond it the moon because the moon rotates at the same rate it orbits the Earth. One side never confronts us, and the other always does.
Likewise, this would mean that if JWST’s depiction of the LHS 1140 bi scene was correct, the side of the planet facing its sun would always be exposed to a lot of heat. This would be the part of the snowball that has “melted” into a liquid ocean.
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Voila.
“Current models suggest that if LHS 1140 b has an Earth-like atmosphere, it would be a snowball planet with a bull’s-eye ocean about 4,000 kilometers [2,485 miles] in diameter,” the statement says, adding that the ocean surface temperature could very well even be a “comfortable” 20 degrees Celsius (68 degrees Fahrenheit).
Alas, although the team confirms that much more work needs to be done, especially with the JWST, to look at the nuances of LHS 1140 b — it’s always nice to be ahead when you’re looking for needles in a giant haystack. And, as MacDonald puts it: “this is a very promising start.”
A preprint version of the study can be viewed on arXiv.
