Notes on star and system formation

The astro news as came out the last few days concerned system-formation. Neural-networks are helping this along, since Google hasn't yet ordered the researchers to hire Sweet Baby Inc.

First up, we learn that in high-energy environments, like where Sagittarius A* and others are gathering matter, stars don't even form. This extends to large planets where O/B stars are forming like at Disc d203-506; ultraviolet is driving that process. Of course these yeet out the helium and hydrogen first. As to smaller bodies weighted to the C and S and iron - I dunno. But honestly, these rocks won't have long even to coalesce into planets before the whole thing implodes again. Overradiation might, further, explain certain of the youngest (visible) galaxies; the ones which quit creating new stars after a few hundred My. No gas, no stars!

For the rest of us, T Chamaeleonis has a solar wind. T Cha is ∼70° inclination to us; visible matter - dirt - is under 1 AU and at ∼20-50 AU. The inner matter is gathering into rock and/or spiraling into the star, but is not our direct question here.

The question here is how the gas and ice leaves an inner solar-system (defined here under 20 AU), where not locked into iceballs like Ceres or giants like Saturn. They are looking at neon and argon, which as noble-gas can't bind into ices; I expect these as a fair proxy for helium, before them. T Cha is ionising so expelling the free neon and argon out of the system; these gasses won't be seen from here for much longer. The force of the wind over time and the concentration of volatiles over time are hereby constrained, excellent data for modellers elsewhere.

And here is a survey of 86 young stars - from Taurus and from that aforementioned Chamaeleon I, both around 600 ly, and Orion at 1600 ly. The survey points to binary stars not having much material, here because they're double-teaming. I don't blame high-ultraviolet; we're looking at dust (infrared), not gas (spectral-lines). Respectable planets can form within binaries but maybe not so much where the stars be under 200 AU apart.