Image of a Planet around Fomalhaut

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You probably shouldn't have posted that. I think it comes under breaking the embargo.

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Well technically none of us are bound by the embargo.

The question is whether it is really ethical to break it, despite not being bound by it. I personally feel it is a good thing that the various records are publically-accessible, and would like it if they remained so, therefore I think it is better to respect such agreements.

Agree.

Ah embargo's.

Meh pm me it if you want.


Especially if it's that inhabited planet of amazonian women and sapient cacti. <<<<<First thing he thought of.

Well, the press release is out. Hubble Directly Observes Planet Orbiting Fomalhaut

The details and papers are up at the Extrasolar Planets Encyclopaedia (which appears to have got years and days a bit mixed up)

Pretty great! Finally an imaged planet around a nearby star! Finally a solar system around an A-type star... and there's two! HR 8799 and Fomalhaut, both in one day! This is seriously awesome!

Hopefully, Fomalhaut-type planetary inferences, such as those of Beta Pictoris and Vega (which the HR 8799 bcd paper has tagged "the Vega phenomenon"), will be confirmed.

Edit: Wait... it just dawned on me, that's a visible light image! Holy crap

Yay arXiv papers. Evidence of more planets in the system?


Optical Images of an Exosolar Planet 25 Light Years from Earth
http://arxiv.org/abs/0811.1994

Abstract wrote:

Fomalhaut is a bright star 7.7 parsecs (25 light years) from Earth that harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. In the plane of the belt, Fomalhaut b lies approximately 119 astronomical units (AU) from the star, and within 18 AU of the dust belt. We detect counterclockwise orbital motion using Hubble Space Telescope observations separated by 1.73 years. Dynamical models of the interaction between the planet and the belt indicate that the planet's mass is at most three times that of Jupiter for the belt to avoid gravitational disruption. The flux detected at 800 nm is also consistent with that of a planet with mass no greater than a few times that of Jupiter. The brightness at 600 nm and the lack of detection at longer wavelengths suggest that the detected flux may include starlight reflected off a circumplanetary disk, with dimension comparable to the orbits of the Galilean satellites. We also observed variability of unknown origin at 600 nm.

Fomalhaut's Debris Disk and Planet: Constraining the Mass of Fomalhaut b From Disk Morphology
http://arxiv.org/abs/0811.1985

Abstract wrote:

Following the optical imaging of the exoplanet candidate Fomalhaut b (Fom b), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. We find that to not disrupt the belt, Fom b must have a mass < 3 Jupiter masses. Previous mass constraints based on disk morphology rely on several oversimplifications. We explain why our constraint is more reliable. It is based on a global model of the disk that is not restricted to the planet's chaotic zone boundary. Moreover, we screen disk parent bodies for dynamical stability over the system age of 100 Myr, and model them separately from their dust grain progeny; the latter's orbits are strongly affected by radiation pressure and their lifetimes are limited to 0.1 Myr by destructive grain-grain collisions. The single planet model predicts that planet and disk orbits be apsidally aligned. Preliminary analysis of Fom b's space velocity does not bear this out. The disagreement might be resolved by having additional perturbers in the Fomalhaut system, for which there is independent evidence from the star's anomalous Hipparcos acceleration. Our upper mass limit of 3 Jupiter masses for Fom b is not affected by these considerations. The belt contains at least 3 Earth masses of solids that are grinding down to dust. Such a large mass in solids is consistent with Fom b having formed in situ.

(emphasis mine)

This day sets the record for the most exoplanet excitement I have ever had in a single day.

So Fomalhaut gets abbreviated to Fom... I quite like that. Haha.

Yeah makes it easier to write, lol.
How does one pronounce "Fomalhaut" anyway? I've heard it pronounced as it's spelled, and I've read that it pronounced "fow-mow-low".

Check the dictionary.
http://dictionary.reference.com/browse/Fomalhaut

[foh-muhl-hawt, -muh-loh]

The first way (foh-muhl-hawt) is the way I pronounce it.

Regarding the paper on the possibility of additional planets, the paper suggests that there might be a 30 Jupiter mass brown dwarf approximately 5 AU from Fomalhaut, based on the Hipparcos detection of proper acceleration. This would put it right in the middle of whatever passes for a habitable zone around a young A-type star. Interesting.

In the light of what we (don't) know about planet formation around massive stars, if such an object is confirmed we can all have a nice argument about whether the definition of planet should depend on deuterium fusion or not.

Some contraints on a second planet.

MMT/AO 5 micron Imaging Constraints on the Existence of Giant Planets Orbiting Fomalhaut at ~13-40 AU
http://arxiv.org/abs/0811.2443

Matthew A. Kenworthy et al. wrote:

A candidate < 3 Jupiter mass, extrasolar planet was recently imaged by Kalas et al. (2008) using HST/ACS at 12.7" (96 AU) separation from the nearby (d = 7.7 pc) young (~200 Myr) A2V star Fomalhaut. Here we report results from M-band (4.8 micron) imaging of Fomalhaut on 5 Dec 2006 using the Clio IR imager on the 6.5-m MMT with the adaptive secondary mirror. Our images are sensitive to giant planets at orbital radii comparable to the outer solar system (~5-40 AU). Comparing our 5-sigma M-band photometric limits to theoretical evolutionary tracks for substellar objects, our results rule out the existence of planets with masses greater than 2 Jupiter masses, from ~13-40 AU and objects greater than 13 Jupiter masses from ~8-40 AU.

So much for the HZ brown dwarf then.

Quote :

Chiang et al. (2008) suggest that Fomalhaut exhibits an “anomalous” acceleration in the Hipparcos astrometry (Perryman & ESA 1997; van Leeuwen 2007), consistent with a ∼30 M_Jup brown dwarf at r ∼ 5 AU. Our observations rule out the existence of an object at this mass at this orbital radius, and the data can rule out the existence of any brown dwarfs (>13 M_Jup) at separations of ∼8-40 AU.

Lazarus wrote:

So much for the HZ brown dwarf then.

Quote :

Chiang et al. (2008) suggest that Fomalhaut exhibits an “anomalous” acceleration in the Hipparcos astrometry (Perryman & ESA 1997; van Leeuwen 2007), consistent with a ∼30 M_Jup brown dwarf at r ∼ 5 AU. Our observations rule out the existence of an object at this mass at this orbital radius, and the data can rule out the existence of any brown dwarfs (>13 M_Jup) at separations of ∼8-40 AU.

Once a similar model has been proposed for Vega. It was supposed to host a <30 Mj within 30 AUs or so. Solstation talks about http://www.solstation.com/stars/vega.htm

Quote :

Modelling simulations by Wilner's team (including www.harvard.edu/hco/astro/people/homepages/holman.html" class="postlink" target="_blank" rel="nofollow">Matt Holman, www.harvard.edu/hco/astro/people/homepages/ho.html" class="postlink" target="_blank" rel="nofollow">Paul Ho, and Marc Kuchner) suggested that the semimajor axis of the planet's orbit may center around 30 AUs -- at Neptune's orbital distance in the Solar System. The simulations also indicated that the planet must be smaller than 30 times Jupiter's mass. A larger planetary mass would cause the observed dust clumps to overlap by destroying and the hypothesized orbital resonances

Then the Neptune-like planet model upcame and the "Vegan dwarf" were not discussed anymore.

Quote :

Other simulations by Nick N. Gorkavyi and Tanya A. Taidakova (Schafer Corporation) of an observed dust disk ring arc at 95 AUs also suggested that there may be a sub-Jovian planet between 90 to 100 AUs out from Vega. The simulations indicated that one (or more) very massive planet within 50 to 60 AUs may have destroyed the inner circumstellar dust disk by gravitational scattering (Abstract for 2002 AAS session 86.07).

There is also an animation (it also seems quite an eccentric jovian):



Maybe the methods and instruments which have allowed the detection of Fomalhaut b and HR 8799's trio could unveil exoplanets also around this bright star.

Meanwhile I'm shifting this discussion at Unconfirmed/Unpublished Planet Catalogue. More infos there.

Neat animation! Thanks for posting that.

It is not really a serious thing, but just notice the striking resemblance among Lord of Rings Sauron's Eye and Fomalhaut's disk...

*Photomanipulation not mine. Taken from TotallyLooksLike.com*




And of course, H.P. Lovecraft was sure the Evil came from the Southern Fish's main star... *lol*

Haha, I made that connection a year or two ago when the first image of the debris disk was released.

Pretty nifty, even if it is an unsurprising result.

The spin-orbit alignment of the Fomalhaut planetary system probed by optical long baseline interferometry
http://arxiv.org/abs/0904.1688

Abstract wrote:

We discuss the spin-orbit orientation of the Fomalhaut planetary system composed of a central A4V star, a debris disk, and a recently discovered planetary companion. We use spectrally resolved, near-IR long baseline interferometry to obtain precise spectro-astrometric measurements across the brG absorption line. The achieved astrometric accuracy of 3 nu-as and the spectral resolution R=1500 from the AMBER/VLTI instrument allow us to spatially and spectrally resolve the rotating photosphere. We find a position angle PAstar=65deg pm 3deg for the stellar rotation axis, perfectly perpendicular with the literature measurement for the disk position angle (PAdisk=156deg pm 0.3deg). This is the first time such test can be performed for a debris disk, and in a non-eclipsing system. Additionally, our measurements suggest unexpected backward-scattering properties for the circumstellar dust grains. Our observations validate the standard scenario for star and planet formation, in which the angular momentum of the planetary systems are expected to be collinear with the stellar spins.

From Dynamics of Cats, it looks like there may be problems with the orbit of Fomalhaut b.

Quote :

Well, Ray Jay reports on a talk by Kalas: there is new HST data, which apparently shows the plant still, but in a slightly wrong place - suggesting maybe an eccentric orbit which crosses the dust ring, which is problematic. Further, the speculation, now, on the excess brightness is that it is a co-orbiting dust cloud, which is starting to be a bit of a stretch

Hmmmm...

I thought Fomalhaut b was undetectable without HST ACS?
What could they use to detect it?

Sirius_Alpha wrote:

What could they use to detect it?

I think this is STIS.
http://online.kitp.ucsb.edu/online/exoplanets10/stapelfeldt/oh/18.html