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.

[1]: https://en.wikipedia.org/wiki/Barnard%27s_Star

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pfdietz 3 hours ago | parent | next [-]

One thing this implies is that the escape velocity of such objects increases linearly with mass, so the surface temperature they can sustain without losing mass increases quadratically with their mass. Massive super-jovian planets can orbit close to their star, limited only by tidal disruption. Some could even orbit within the outer envelope of the star for quite some time.

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hparadiz 2 hours ago | parent | prev | next [-]

If a brown dwarf is right on the edge of stardom would it start protium fusion in only the part of itself that is the right pressure and then slowly burn out or would that ignition precipitate a pressure wave through the entire body forcing fusion to begin everywhere?

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F3nd0 an hour ago | parent | prev | next [-]

I kind of assumed the artist’s impression was working with perspective? The images shown in the sidebar seem to picture them at different relative sizes.

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walrus01 4 hours ago | parent | prev | next [-]

> It is estimated that Jupiter is essentially the largest any gas giant can get

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

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delta_p_delta_x 4 hours ago | parent | next [-]

Yes; I was under the impression that from context it was clear what I was talking about. In astrophysics, to avoid precisely this confusion, the convention is to use the adjective 'massive' when comparing, well, masses, and 'largest'/'smallest' for the dimension of length and its higher powers (radius/diameter/area/volume). For instance:

> the Sun is 3.33e5 as massive as Earth.

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Foskya 4 hours ago | parent | prev [-]

But... he literally said in the following sentence that adding more mass does not change size, implying that he is talking about diameter, not mass.

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walrus01 4 hours ago | parent [-]

Correct, but the link for "super jupiter" also goes to something that astronomers are fairly sure is 1.38x the diameter of Jupiter. Much less massive of course. Meaning Jupiter's diameter is not an absolute hard limit nothing can be larger than.

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.

	▲	nullsanity 2 hours ago \| parent [-]
		Nobody said it was, he said it was "pretty much". Y'all can't read anymore.

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PaulHoule 4 hours ago | parent | prev | next [-]

Nice charts in this paper that support this thesis

https://pmc.ncbi.nlm.nih.gov/articles/PMC6525489/

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ck2 2 hours ago | parent | prev [-]

NASA exoplanet catalog has a neat system/star view

* https://science.nasa.gov/exoplanet-catalog/cd-35-2722-b/