this would actually be a planet, based on my understanding of celestial bodies?
moons are natural satellites orbiting planets. this "moon" is orbiting a brown dwarf.
I guess it is more of a derivative of the question: "in which bucket should we put the brown dwarf? Is it a star or a planet?".
The answer is neither of course; but since it is more closely related to stars than to planets, I'm more inclined to call this satellite an exoplanet (instead of exomoon).
That being said it is still a nice finding, way more difficult to discover than "normal" exopanets.
An important phrase from the article to consider before commenting: "This system is somewhat hard to define using Solar-System-based words like ‘planet’ and ‘moon’"
A small dense planet, which orbits a star, is orbited by a larger gaseous moon. It's interesting the discovery is in Chile which has some of the best night skies, a Class 1 on the Bortle scale specifically in the Atacama Desert. Hoping to make it out there one day.
I wonder if this thing in turn has something in orbit around it? At the size I wouldn't surprise me if it had satellites of its own in orbit, leaving open the question of what to call them. (I'm no astrophysicist, is this really possible I don't know, but it wouldn't surprise me. What would surprise me is if we could detect them)
Worth noting that the artist's impression is... not accurate. Both CD-35 2722 b (the brown dwarf orbiting the primary star) and CD-35 2722 b I (the exomoon orbiting the secondary) should be much closer in size. It is estimated that Jupiter is essentially the largest any gas giant can get; adding more mass will simply increase density and interior temperature until deuterium and lithium fusion and brown dwarfdom, and then at around 80 Jupiter masses, protium fusion and stardom.
Look at Barnard's Star[1], which is actually a fusing red dwarf star: it is not much bigger than Jupiter.
I really wanna call it a planet. It doesn't orbit a proper star, but if we call similar objects that don't orbit a star at all rogue planets I don't see why not call it just a planet.
Outside of the small probability that this may assist us in the future, has looking beyond our moon ever benefitted or even affected humanity in any way?
Monitoring "space weather" (paying attention to the sun/solar flares/CMEs etc) is important to keeping our earth orbiting satellites functioning. (That's without getting into what a modern "carrington event" would look like.)
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[ 0.24 ms ] story [ 20.0 ms ] threadThat being said it is still a nice finding, way more difficult to discover than "normal" exopanets.
Isn't the dividing line between the largest possible gas giants and the smallest brown dwarfs a bit fuzzy?
https://en.wikipedia.org/wiki/Substellar_object
Look at Barnard's Star[1], which is actually a fusing red dwarf star: it is not much bigger than Jupiter.
[1]: https://en.wikipedia.org/wiki/Barnard%27s_Star
You could basically have a bath in a brown dwarf, sure you might not last long, but still...
but Nancy Grace Roman Space Telescope WILL find Earth-sized exoplanets and even REAL moons
I am stupid-excited to see it launched/first-light in my remaining lifetime (Musk better not screw it up)
For perspective on the technology, JWST "only" has 28mbps downlink
NGR has 500mbps downlink, that's right 1.5 TERABYTES PER DAY download speed
all from ONE MILLION MILES AWAY in L2 (11 seconds ping time!)
Technology is getting amazing!
I find Earth-sized exomoons quite exciting. Imagine the civilizations that can develop around those.
https://youtube.com/shorts/qreL7htXp98?is=G9zJVbpMT0yZsLQ-
(tl;dw it's an exciting discovery but moon is the wrong terminology for what was found)