Earth-like LHS 1140b May Feature The First Atmosphere Found On Exoplanet | Hackaday

Skip to content

Finding another planet outside of our solar system that can comfortably be called ‘Earth-like’ is one of those discoveries that — if confirmed — would be a major event. The complication here is that with every exoplanet that we discover through observations, determining the type of planet is hard enough, never mind figuring out whether it has an atmosphere, much less what’s in that atmosphere. This makes a recent report on LHS 1140 b rather exciting, as it strongly suggests that this super-Earth may have something close to an Earth-like atmosphere.

In the paper by [Collin Cherubim] and others in Science, the findings of helium occasionally escaping from its atmosphere have led to considerable excitement, as this time-variable atmospheric escape of helium suggests a helium-rich upper atmosphere that’s further depleted in hydrogen.

It should be noted, of course, that these assumptions are based on observations from roughly 49 light-years away, so there’s always some room for later adjustments. Even if confirmed, the star that LHS 1140b orbits is a red dwarf, with a nearly 25-day orbital period and light levels less than half of what Earth receives from the Sun. This would make the surface of LHS 1140b with its proposed oceans rather dim, even if it’s conceivably at temperatures well within the comfort range of us Earth-based mammals.

At 49 light-years distance, it’s also not close enough that — barring an FTL drive — we could do direct observations or visitations, but if these results hold, it’d be on the short list along with a number of other plausibly habitable exoplanets to check out once we build that first warp drive-powered starship.

14 thoughts on “Earth-like LHS 1140b May Feature The First Atmosphere Found On Exoplanet”

Here on earth natural accumulations of helium are the result of radioactive decay. Maybe we shouldn’t focus our planet search on those planets that have so much of it that you can detect it from here.

Report comment

Reply

No, on Earth it’s because that’s all that’s left over: the early atmosphere has lost all its helium (the hydrogen bonded, the helium just escapes).

This is a much more massive planet (5.6x Earth and 1.7x radius so about 50-60% higher surface gravity) so the helium retention time would be much longer.

And it’s not that there’s a lot of helium, but because helium escapes, it’s easier to detect since it’s over a larger area. The key isn’t the helium, it’s that there’s an atmosphere at all.

Report comment

Reply

I’ve always been amazed at the pull-a-rabbit-out-of-a-hat nature of these long distance astronomical measurements. I’d dare brand it “1D astronomy,” where essentially you are trying to glean profound data from a single pixel over a long period of time.

Report comment

Reply

It’s actually not "single pixel" – this spectrograph used an echelle grating (like many/most) where the incoming light is split basically into wavelengths spread over 2D using multiple diffraction gratings, and then you image the spectrum, so you get a lot of data. Obviously when you’re focusing on a small portion of the spectrum it’s a little more like "single pixel", but part of the confidence you have in saying something like this is that absorption lines are pretty wide and you can fit them to various parameters to ensure it makes sense.

Spectrometry’s amazing. There’s this poem from Robert Frost in 1916 called "Choose Something Like a Star" where he laments as to how inscrutable stars are ("Say something! And it says, “I burn.” // But say with what degree of heat. // Talk Fahrenheit, talk Centigrade. // Use language we can comprehend. // Tell us what elements you blend. // It gives us strangely little aid"). It always struck me that Frost’s poem was just before the point where it was common knowledge that we could know all of those things from stars – even by the time it was written, we were doing it, but it was very new. (For reference, the poem isn’t actually about actual stars, but in reference to other poets being so difficult for people to understand).

Report comment

Reply

Good point. I’ve put some effort into imagining the colonization of an “earthlike” planet, and it always seems like a stretch unless first you “terraform” before sending humans. A resource as seemingly simple as soil is complex enough to keep PhDs busy studying its mystery her at home. If you can’t do agriculture, I’d hardly call it habitable.

Report comment

Reply

We’re not even able as a species to safeguard our living here and mitigate the effects of climate change so terra forming anything that is so far and such a long-term goal is clearly out of reach.

Report comment

Reply

I really don’t think the various forms of that argument are very logical.

It’s like saying you shouldn’t be attempting a repair job on some piece of common rubbish until you have mastered caring for...