Imaged Planet at HD 1160?

The Gemini NICI Planet-Finding Campaign: Discovery of a Multiple System Orbiting the Young A Star HD 1160

Quote :

We report the discovery by the Gemini NICI Planet-Finding Campaign of two low-mass companions to the young A0V star HD 1160 at projected separations of 81 +/- 5 AU (HD 1160 B) and 533 +/- 25 AU (HD 1160 C). VLT images of the system taken over a decade for the purpose of using HD 1160 A as a photometric calibrator confirm that both companions are physically associated. By comparing the system to members of young moving groups and open clusters with well-established ages, we estimate an age of 50 (+50,-40) Myr for HD 1160 ABC. While the UVW motion of the system does not match any known moving group, the small magnitude of the space velocity is consistent with youth. Near-IR spectroscopy shows HD 1160 C to be an M3.5 +/- 0.5 star with an estimated mass of 0.22 (+0.03,-0.04) M_Sun, while NIR photometry of HD 1160 B suggests a brown dwarf with a mass of 33 (+12,-9) M_Jup. The very small mass ratio (0.014) between the A and B components of the system is rare for A star binaries, and would represent a planetary-mass companion were HD 1160 A to be slightly less massive then the Sun.

Nice! Certainly raises further questions about where the upper limit of planethood lies: is a 20 Jupiter mass object orbiting an M-dwarf more or less likely to be a planet than a 20 Jupiter mass object orbiting an A-dwarf?

I think we've seen a clear correlation between the mass of the star and the mass of the planet. So I would venture to say that a 20 M_J object orbiting an A type star would be more likely to be a "planet" than a 20 M_J object orbiting an M dwarf. M dwarfs don't seem capable of scrounging up enough material to form a gas giant planet through core accretion, so gravitational instability probably produces objects like the directly imaged M dwarf planet candidates that have been recently reported. Gravitational instability could produce anything from planetary mass bodies up through brown dwarfs and so if you let the formation method be the discriminate between planets and brown dwarfs, I'd say it's more likely that a 20 M_J around an A-type star more likely formed through core accretion than if the host were an M dwarf.
Thoughts?

In my opinion 10 jupiter mass limit for the planet would be the best

Why 10 M_J specifically? As opposed to 10.5 M_J or 9.5 M_J?

And how would you treat the ν Oph system, with two ~20 M_J companions in nice orderly orbits? What about BD 20+2457?

According to me - which I'm quite not an expert - I think the uppermost mass limit for exoplanet could be furtherly broadened in the future. The so called "brown dwarf desert" could also include very massive planets with masses up to 35 Jupiter masses.

Sahlmann et al. (2011) has already raised it up 25 Jupiter masses.