Barnard's Star! - I can hear the groans from here. No seriously, Barnard's; or Proxima Ophiuchi which Gliese catalogued 699. The ESPRESSO "VLT" 'scope found this one.
As a radial nontransit this reading has a minimum mass: 0.37 M⊕ sin i. If it were a transit it would sit three times Mars' mass and half Venus'.
The orbit is 3.1533 ±0.0006 days so 0.023 AU. Zero eccentricity and no moon at this distance, so we should all safely assume no rotation. This late in the system's age we can disregard tectonics.
They are talking other signals: 3.15, 4.12, 2.34, and 6.74 days. The furthest would be 0.17 AU, the closest - which skates very close to the confirmed planet - 0.019 AU. The outer one would get incident-flux 2.4 S⊕ and the inner, 10.1, all more than Venus gets. I'd rather they'd calculated the irradiance of the planet they tell us they'd confirmed, before asserting a "temperature". Overall flux looks upward of Mercury's 6.674.
Add all this up: Barnard b has no air. They're guessing a sunfacing albedo of rock, 0.3; for 400 K. Back of the place should retain some ice tho'.
No comments:
Post a Comment