Two newsbits came in last weekend: first, limb darkening - as a means to finetune the surrounding shape of a stellar disc. That's useful for ascertaining starspots and, of course, planetary transits. Also in the news is a measurement of stellar winds from 61 Cygni, 70 Ophiuchi, and epsilon Eridani. These are quite close to us. I think by 61 Cygni and 70 Ophiuchi, binaries both, they mean A.
61 Cygni's stars are both 6.1 Gy old, and about 70%/63% solar mass; 70 Oph at 1.9 Gy and 90%/70%. The stellar wind of each suggests that one or the other is losing mass an order of magnitude as our (stronger) Sun. I much doubt that any of these four be pregiant on the mainsequence. Epsilon Eridani on the other hand is new, like T Cha.
The stars share in common: magnetic field. Strong fields mean mass loss, and may explain 61 Cygni's severe case.
Does being in a binary "juvenate" a star, so it behaves like εEri?
Anyway if we can figure a field from either direct imaging or the wind, we can probably figure other parameters (starquakes are also good for this). Thus improving transit-measurements if any. Or, constraining if a star even has planets or water in HZ.
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