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Discussion (41 Comments)Read Original on HackerNews
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
That does not appear to be the case if we mean mass, not diameter.
https://en.wikipedia.org/wiki/Super-Jupiter
https://en.wikipedia.org/wiki/CoRoT-3b
> the Sun is 3.33e5 as massive as Earth.
https://en.wikipedia.org/wiki/HAT-P-1b
It also orbits its star in only under 5 days, so a few theoretical visualization/renderings of it would probably be quite spectacular.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6525489/
That being said it is still a nice finding, way more difficult to discover than "normal" exopanets.
'Planet' comes from the Greek word for 'wanderer' which was very useful for labeling the handful of bright stars that moved through the heavens in a pattern. Then we got to the Space Age and kept calling them (and similar new additions) 'planets' even as we learned far more about them. And immediately there's a problem. Setting aside Pluto (and the Sun), you've still got Mercury on one end (5% of Earth's mass, and smaller than several moons) and Jupiter on the other end (320% of Earth's mass - more than everything else in the solar system put together, and over 1000 times Earth's volume). "Planet" stops being a word you can use with any sort of detail. (Thus the IAU definition battle and Pluto's "demotion".) Astronomers have pretty good terminology for stars, but once you go sub-stellar, the labeling rapidly gets difficult, and for good reason.
...do they though?
The "proper" terminology says all main sequence stars are dwarves, but nobody calls them all that in practice. Some astronomers insist on saying "yellow dwarf", but some don't really bother. In general having the only two kinds of star be "giant" or "dwarf" is contentious, but it's also contentious that there isn't a name for whatever is in the "middle". "Main-sequence star" is a broader category and doesn't apply. They're all "stars", obviously, so that isn't specific enough.
The only decent terminology is for the spectral classes, but those only work as long as you look at spectra. The moment you try to figure out what the theory says those stars would look like as proper 3D objects, things get very messy. You also immediately get the issue that star size and brightness goes O>B>A>F>G>K>M. So... it's alphabetic except it isn't. And C is something completely different and doesn't fit the brightness classification at all.
About ESO [1]
> We are an intergovernmental organisation established in 1962 supported by 16 Member States (Austria, Belgium, Czechia, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), our host country Chile and strategic partners.
So Chile has a distinct status, hence the margin...?
[1]: https://www.eso.org/public/about-eso/
You could basically have a bath in a brown dwarf, sure you might not last long, but still...
“A subsatellite, also known as a submoon, moonlet or informally a moonmoon, is a "moon of a moon" or a hypothetical natural satellite that orbits the moon of a planet”
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
The exact model limit is unclear, but the physics modelling is relatively straightforward.
see the Classification header of the page
> The star is being orbited by a brown dwarf, an object too massive to be a planet but too small to be a star.