TOI-4600

The transiting-scope TESS is still at it. Ismael Mireles et al. have reported in on the object-of-interest 4600.

Gaia meanwhile has data on this star as well, out at parallax 4.620 ±0.011, which is sadly single-digit (216.45 parsecs). And it's a dim one, a K slightly over 2/5 our own Sun's luminosity. Age isn't well-constrained: 700-5100 My. They do think they've constrained its mass at 0.89 ±0.05 M_⊙. This wasn't done by Kepler on account there's no radial-velocity constraint on the planets.

Right: that's a plural. Two of the things are transiting the star. However much they weigh, they're big: 6.80 ±0.3 and 9.42 ±0.4 Earths. Both are Saturn-size.

Metallicity of the star is 0.16 ±0.08 Fe/H. Usually hot-Jupiters form at 0.25; our Sun's is a, er, hot topic but is typically considered 0.012 or less. One reason why the paper figured this star for a later-generation star therefore young. I would guess that at least the inner planet is high-mass with a thick gaseous envelope, not as Saturnlike as its volume suggests.

Neither of these two are in the habitable zone. The inner one 0.35ish AU gets a little more warmth than Earth and that'll be in the infrared, so its moons (if any) are venuslikes. The outer one 1.1-1.2 AU (it's only been caught transiting twice, so there's less constraint) is just plain cold. They think cold as Ceres, based on similar sources as John Cougar Mellencamp's statistics (just give us the stellar flux, guys).

Anyway the outer one could run elliptic. Again, little constraint, beyond that it shouldn't be mixing Hills with the inner one. At least we know the planets aren't resonant (29:5? lol). It could be that they were 6:1 in the past, though; that might contribute to present eccentricity.

Could there be an earth-habitable planet, in between? High metals imply that planets in the habitable zone, if they have oxygen, won't have ozone. And I'm concerned that the inner planet is a heavy-hitter with a wide Hill.