TOI-1136 revisited

The antiHawaiians using HIRES and the spacers on the TESS 'scope, in concert, have delivered a catalogue. A skim through this humble blog has picked up TOI-1136 at Praesepe. The researchers, Michelle Hill and others, figured this one worth the extra 157 total observations. Hill contributed to the dedicate paper to that one, before; now, to this sequel (pdf).

As noted earlier the TOI-1136 star is only 700My on main-sequence. So it is... volatile. Back in 2022 a skeptic (I wasn't a skeptic) might ponder starspots or mere fluctuation. And indeed the survey must scratch out a few Transits Of [then-]Interest - tho' not many, tho' not TOI-1136.

TESS was supposed to be observing this one again from 30 January; but the 'scope has experienced some off-time this spring, so I dunno.

What they got as of end-of-2023 was confirmation of six hot planets "b"-"g". Also a seventh dimming may recur at a Mercurial 80 days - although as-ever, more observations are needed for less-frequent patterns. 80 days is, they admit, abutting 2:1 with the 39.5 day "g"; it may be an alias.

In what the dedicate paper has constrained, the six confirmed masses are all subNeptunian and superEarth. Only "b" is rock-ably dense; the others are slightly thicker (given error-bars) than water. They're as "puffy" as we thought eighteen months ago. I assume heavy gas-envelopes and obscurant clouds - the researchers say again, hydrogen/helium. Sudarsky might say "IV" excepting that I don't think he was ever considering worlds as transitional as 700My-old worlds must be.

And yeah, I do see Sudarsky's influence here; they're using "equilibrium temperature" which depends on [zero] albedo. (They should be leaning more to insolation: 365, 213, 84, 49, 31, and 18.) Assuming total darkness: 737 K for "e", 658 K for "f", 574 K for "g". 350-800 K, recall, was Sudarsky's III range of cloudless planets, hot blue Rayleigh, low-albedo but not zero. That's where those hydrogen/helium envelopes might actually be deep enough for nontransparence. Anyway I assume that like Venus they're all much hotter than that at their surface. I have high hopes "g" at least will settle into III, later.

The comparisons (for c-g) are with Kepler-11 (older) and V1298 Tau (almost T Tauri); at 700My this system fits in between.