ScienceDaily had another supermassive flare yesterday. The highlight was the observation of two somewhat-close extrasolar planets. We cannot guarantee that all planetary nebulae even make planets, so the stars TOI 560 (103 ly) and HD 63433 (73 ly) are as close as we get.
The issue is a gap between "Super Earths" up to 1.6-1.75 Earth mass range, and the miniNeptunes going from twice Earth on up. Each has a peak, and between them is a paucity. The super-Earths are considered to be more like super-Venus in that an atmosphere is expected but not radially dominant, as over Neptune. Too hot, too small; escape velocity of low-mass gas, etc etc. The super-Neptunes would be high in hydrogen and helium, which escapes from Venus (famously) but not from Uranus.
Up to now that above was just their opinion, man. Suppose the super-Earth was like... Earth, and never collected a gas envelope in the first place. Or maybe the "mini Neptunes" are like... Neptune, except that they lost their hydrogen and are now water worlds. Or maybe carbon planets?
TOI 560 and HD 63433 show that the theorists' earlier theory should be considered normative. Their planets are losing their atmospheres. They will end up as super-Earths like close-binaries become supernova-bound or look prematurely aged.
Honestly upon being reminded of that super-Earth-from-birth theory, I have to say: it was never a winner. Many planets migrate closer to their star, if there be a Jupiter out there to force a resonance. I take the water-world (or carbon-world) theories more seriously. Although, in light of this new finding, those should be considered edge-cases, to be mooted where we know the atmosphere cannot be lost. Admittedly I should expect such out where it's colder, which isn't a good hunting ground for transits.
STATISTICS 12/15/23: Checking HD 63433 against the Hyades.
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