The authours have done a very nice job with the data reduction and demonstrating that they have the sensitivity for their reported results, so it is a very solid upper limit there.

Regardless, it was known from the first paper in 2008 that we’re almost certainly looking at a cloud of dust. The issue is whether the dust is in orbit about a planet (we can’t see the planet’s flux because its surface area is so small) or is it a gravitationally unbound clump of dust from a recent collision?

…..
Red Matter or Parallax, your choice

Nice

Probably the best scene in STOS. William Windom outdid Shatner

Gravity is a strange thing, if there is a clump there is gravity. A visible clump (from 25 ly) means a lot of gravity, which means we are probably looking a preproto-planet, which is far more interesting than a planet (we have a lot of them to study).

This is something new to study, a clumping dust ball, a super dust bunny, sweeping up more dust as it travels in ond out of the accretion disk. Get a doppler on it see if it is spinning. You Astronomers may have the rarest of rare (for now) a pre-pre-planet.
I smell papers (mention me as a contributor, please)

There is no bad Astronomy in this!

Captn Tommy

The argument against the collision remnant is that this would be far more likely within the dust ring rather than outside it, so perhaps if this is the explanation we should expect to be seeing more objects like Fomalhaut b within the debris ring. Then again the issues with speckles and image noise mean that we would probably miss such objects within the dust ring.

Certainly we cannot say that Fomalhaut b represents the direct detection of a planet though… the infrared results show we are not seeing the planet itself even if one is actually there.

As for planet definitions… oh no not this again…

* Derived from Gamma Doradus variable, Lambda Bootis metal poor star with a Vega style protoplanetary disk – this stars other traits.

I like it! We really need a naming scheme that goes beyond mythology and constellations and is easier to remember then simple number strings.

Also, I was interested to see that that star shows about one third the metallicity of the sun. And yet it has at least 4 planets and an extensive debris disk. I’d always sort of assumed that low-metallicity stars just didn’t have much going on as far as planetary systems.
I wonder if systems like that have significantly more comets than ours? With planets at such a great distance (for flinging KBOs inward), and some of that debris must be composed of volatiles if the system’s metallicity is that low.

Good point – exactly. Plus there’s the fact that the idiotic IAU definition specifically and absurdly excludes all exoplanets from counting as proper planets anyhow. Arrgh! Don’t get me started on that topic..

Sounds like I already did
I had no idea about that little clause in the IAU definition, though. Exoplanets don’t count as “proper” planets? How heliocentric of them

I thought Fomalhaut b had been independently confirmed by other teams & instruments? Seemingly not. [A quick google check seems to say not - only HST could find it - ed.]

Still I guess that means the honour for first photographically spotted exoplanets goes to ‘Gadolabove’* as I call HR 8799. (Click my name for more on that star and its worlds via kaler’s Stars site.) They, at least, have been confirmed and remain planets right?

@ 36. Joseph G :

Seriously, though, this sounds like we’re gearing up for a rehash of the Pluto argument. Obviously there’s a lot of stuff orbiting this star. Even if there were a nice big spherical planet, could it really be said to have cleared its orbit? And given that much material, it’s more than likely that there are some protoplanets in there somewhere.

Good point – exactly. Plus there’s the fact that the idiotic IAU definition specifically and absurdly excludes all exoplanets from counting as proper planets anyhow. Arrgh! Don’t get me started on that topic..

Seconding the “win!” for #11 Staar84 & #18 ThomasK too.

———

* Derived from Gamma Doradus variable, Lambda Bootis metal poor star with a Vega style protoplanetary disk – this stars other traits.

No, no, you don’t understand! They’re just saying that for the grant money. Everyone knows that the government spun the big randomized grant wheel right after the new year. This year, the big bucks are going to “Scientists who doubt the existence of exoplanets.”

That’s all

@11 Staar84: Lost a planet, the scientists have. How embarrassing.
Win!

@18 ThomasK: “People of Fomalhaut b, your attention please. This is Prostetnic Vogon Jeltz, of the Hyperspace Planning Council. As you will no doubt be aware………”

This whole thread is a massive orbiting ring of assorted win particles.

I beamed them down to Formalhaut b.

But there is no Formalhaut b!

DON”T YOU THINK I KNOW THAT! There was, but not any more…

@31 amphiox: THIS Fomalhaut b doesn’t exist.

Well, that kind of depends on precisely what it was we gave the name Fomalhaut b to. Was it the specific few pixels we saw on the images and believed to be a planet, or was it to the actual planet presumed to be circling that star, whose existence was inferred from the structure of the dust ring, and then thought to be confirmed by direct observation?

It’s like a witness picking a suspect out of a pile of pictures, saying “that’s the thief who stole the purse”, but choosing the wrong guy in error. The picture chosen wasn’t the thief, but the thief (most likely) still exists, as inferred from the observation of the absence of the purse.

How do you do that? I’m not a disk or mid-IR specialist, I don’t know. Hopefully someone will tell me if that’s plausible.

@27 oooa: One interesting and complicating factor here is that Fomalhaut has a distant red dwarf companion, TW PsA. I saw a talk at the latest AAS meeting that suggested gravitational perturbations from these distant companions could explain why something like 1/3 of all planets are not orbiting in the same plane as their parent star’s equator.

@31 amphiox: THIS Fomalhaut b doesn’t exist. I admit, the distinction gets tricky, particularly with systems like 55 Cancri where people have re-defined the orbits from time to time based on new data- is it still referring to the same orbiting object as before? (usually yes, if the new orbital parameters are within the same range as the old ones)

And the first planet found orbiting the star Fomalhaut will by convention be named Fomalhaut b, won’t it?

Seems to me we shouldn’t be saying that Fomalhaut b doesn’t exist. Current evidence still seems to suggest that most likely it does. It’s just that the picture we thought we had taken of it, probably isn’t it.

J/P=?