Interferometric study of exoplanet host stars

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Interferometric study of exoplanet host stars

Post by Lazarus on 13th November 2015, 1:57 pm

Ligi et al. (2015) "Radii, masses, and ages of 18 bright stars using interferometry. And new estimations of exoplanetary parameters"
http://arxiv.org/abs/1511.03197

Including detailed study of 55 Cancri, which seems to have been a problematic case in some previous studies. There appear to be two possible solutions for the age of 55 Cancri, the young solution is 31 Myr (!) and a mass of 0.97 solar masses, the old one is 13 Gyr and a mass of 0.87 solar masses. The stellar mass estimated from interferometry and the density measurement from the transit of 55 Cancri e agrees better with the young solution. Hmmmmm.
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Re: Interferometric study of exoplanet host stars

Post by Shellface on 13th November 2015, 6:53 pm

…And the fact that 55 Cancri isn't entirely coated in spots tells us that it didn't just reach the main sequence, chi-square be damned.

The model-independent mass is 1.3σ from their "old" mass, and 0.7σ from the von Braun et al. mass (whose radius has 3 times better precision), which isn't exactly ground-breaking evidence. So, I would advise against taking this as anything much.

Still, it's good to see more direct observations of stellar radii. There have been quite a few large works on the subject recently, and the levels of precision obtained have made direct observations a capable test of stellar models.

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