Possible planets around SAO 206462 (Lupus)

http://www.nasa.gov/topics/universe/features/possible-planets.html


"What we're finding is that once these systems reach ages of a few million years, their disks begin to show a wealth of structure -- rings, divots, gaps and now spiral features," said John Wisniewski, a collaborator at the University of Washington in Seattle. "Many of these structures could be caused by planets within the disks."

The newly imaged disk surrounds SAO 206462, an 8.7-magnitude star located about 456 light-years away in the constellation Lupus. Astronomers estimate that the system is only about 9 million years old. The gas-rich disk spans some 14 billion miles, which is more than twice the size of Pluto's orbit in our own solar system.

The Subaru near-infrared image reveals a pair of spiral features arcing along the outer disk. Theoretical models show that a single embedded planet may produce a spiral arm on each side of a disk. The structures around SAO 206462 do not form a matched pair, suggesting the presence of two unseen worlds, one for each arm.

Wow, that's a nice image!

Interesting. Though I would prefer to have more direct evidence of the planets.

What's the current score with predictions of planets from debris discs anyway? Beta Pictoris b seems to match the predictions pretty well, but I'm not sure anything else does. Fomalhaut initially looked like it might be another case but it doesn't seem to be matching expectations in follow-up observations...

SpaceRef: Spiral Structure of Disk May Reveal Planets

Image of the disc around the F8 star SAO 206462 reveals spiral structure.

Also http://arxiv.org/abs/1202.6139

Nothing new here other than what is reported here, right?

Looks like no.

Merge the threads!

Done

SAO 206462/HD 135344 b confirmed?

How Bright are Planet-Induced Spiral Arms in Scattered Light?

Quote :

Recently, high angular resolution imaging instruments such as SPHERE and GPI have discovered many spiral-arm-like features in near-infrared scattered light images of protoplanetary disks. Theory and simulations have suggested that these arms are most likely excited by planets forming in the disks; however, a quantitative relation between the arm-to-disk brightness contrast and planet mass is still missing. Using 3D hydrodynamics and radiative transfer simulations, we examine the morphology and contrast of planet-induced arms in disks. We find a power-law relation for the face-on arm contrast (δmax) as a function of planet mass (Mp) and disk aspect ratio (h/r): δmax≈((Mp/MJ)/(h/r)1.38)0.22. With current observational capability, at a 30 AU separation, the minimum planet mass for driving detectable arms in a disk around a 1 Myr 1M⊙ star at 140 pc at low inclinations is around Saturn mass. For planets more massive than Neptune masses, they typically drive multiple arms. Therefore in observed disks with spirals, it is unlikely that each spiral arm originates from a different planet. We also find only massive perturbers with at least multi-Jupiter masses are capable of driving bright arms with δmax≳2 as found in SAO 206462, MWC 758, and LkHα~330, and these arms do not follow linear wave propagation theory. Additionally, we find the morphology and contrast of the primary and secondary arms are largely unaffected by a modest level of viscosity with α≲0.01. Finally, the contrast of the arms in the SAO 206462 disk suggests that the perturber SAO 206462 b at ∼100 AU is about 5−10MJ in mass.