More planet news from the Extreme Solar Systems conference
In addition to the Jupier like planet (did I mention that I like that result…?)
the California-Carnegie-AAT team has several more long period jovians, possibly with low eccentricity orbits.
Looking at known planet hosts, 179 stars, 25 are known already to have second planets (including 5 triples and 2 quads) and 35 are showing long term velocity trends consistent with giant planets in long period orbits.
They see many indications or resonant coupling between planets in the multiple systems (I recall 1/4 of the planets being in mean motion resonances, but I can’t find a hard source for that number).
Some brown dwarfs are being found, including new low mass ones – for wide separation systems there is clear overlap in masses, the lowest mass brown dwarfs overlap in mass with the highest mass planets, to the extent that the distinction makes any sense. At short orbital periods the data may show a clean break in mass between planets (roughly less than 10 jupiter masses) and brown dwarfs (roughly > 13 jupiter masses)
Texas group showed a recently announced double planet system around a low metallicity star, jupiter mass and half-jupiter mass at 200 and 500d orbital period, metallicity is -0.7 (or one fifth solar) – star is HD155359, a 0.9 solar mass star that is old (! 10 Gyrs)
I don’t think the “Rare Earth” hypothesis is holding up well, the pieces of the argument are being dismantled wholesale as we find more systems and gain more understanding.
There are more low mass planets around K and M stars, but people are not announcing formally stellar identities until candidates are confirmed.
There is now data on Barnard’s star and Proxima Cen with good velocity sensitivity (~ 3 m/sec).
Barnard’s star (old nearby M dwarf) is active and velocity variability correlates with photometric variability –
Proxima Cen is very variable, but the fluctuations in velocity do not correlate with the fluctuations in brightness. Maybe something there if the data can be dug into.
Should have better than 1 m/sec observations with UVES spectrograph on the VLT telescope.
This will get to sensitivity of one earth mass in the “habitable zone” (which isn’t really, the star is variable).
Maybe there is a low mass planet in moderately short period orbit around Proxima Cen – be interesting if that turnsout to be the case.