Image of a Planet around Fomalhaut

And now things get weirder...

Collisional Evolution of Irregular Satellite Swarms: Detectable Dust around Solar System and Extrasolar Planets

Proposes that Fomalhaut b might be a low-mass planet surrounded by a swarm of irregular satellites, in an orbit that crosses the dust ring. If so, it would help if it were a binary planet in order to get higher accretion rates with lower planet mass - this would minimise disruption to the dust ring over the age of the system.

http://www.stecf.org/conferences/HST3/presentations/mon_s_3/kalas4hst_sm.pdf

Quote :

If belt crossing, then many new observations possible, such as SL-9 impacts to explore atmosperic chemistry

It seems there is no orbit problem.

On page 602:

"We recover Fomalhaut b approximately 0.5 arcsec north of its 2006 position.
The new data are consistent with a bound Keplerian orbit nested within the belt."

http://files.aas.org/aas217/aas217_abstracts.pdf

New Scientist has an article about the discussion of Fomalhaut at Extreme Solar Systems II: New doubts about 'poster child' of exoplanets.

Whatever's going on at Fomalhaut it is clearly not a simple system!

Seems to be a bit of a debate going on over this one... Nature News article

I'm kinda hoping the low-mass binary planet surrounded by a collision swarm idea will hold up...

Capture of Irregular Satellites via Binary Planetesimal Exchange Reactions in Migrating Planetary Systems

Seems the irregular satellite collision cascade scenario holds up, a possibility is that Fomalhaut b is currently in the process of outward migration.

Infrared Non-detection of Fomalhaut b -- Implications for the Planet Interpretation
http://arxiv.org/abs/1201.4388

Quote :

The nearby A4-type star Fomalhaut hosts a debris belt in the form of an eccentric ring, which is thought to be caused by dynamical influence from a giant planet companion. In 2008, a detection of a point-source inside the inner edge of the ring was reported and was interpreted as a direct image of the planet, named Fomalhaut b. The detection was made at ~600--800 nm, but no corresponding signatures were found in the near-infrared range, where the bulk emission of such a planet should be expected. Here we present deep observations of Fomalhaut with Spitzer/IRAC at 4.5 um, using a novel PSF subtraction technique based on ADI and LOCI, in order to substantially improve the Spitzer contrast at small separations. The results provide more than an order of magnitude improvement in the upper flux limit of Fomalhaut b and exclude the possibility that any flux from a giant planet surface contributes to the observed flux at visible wavelengths. This renders any direct connection between the observed light source and the dynamically inferred giant planet highly unlikely. We discuss several possible interpretations of the total body of observations of the Fomalhaut system, and find that the interpretation that best matches the available data for the observed source is scattered light from transient or semi-transient dust cloud.

The super-Earth with irregular satellite swarm model continues to hold up then, despite problems with the circumplanetary disc and giant planet scenario...

Lazarus wrote:

The super-Earth with irregular satellite swarm model continues to hold up then, despite problems with the circumplanetary disc and giant planet scenario...

A super-earth? I guess I'm missing something.

Edasich wrote:

A super-earth? I guess I'm missing something.

If the object's orbit crosses the disk, then it must be less than 10 M_e to avoid disrupting the disk, according to the paper. Such a planet would not have been detected by HST. So we're forced to consider that what HST saw is a cloud of debris resulting from planetesimal collisions. This cloud may, or may not, be bound to a planet, but if it is, the planet must have a mass in the super-Earth regime.

I see. I hope there is really a planet around Fomalhaut.

This does leave open the question of what is responsible for the disc offset/eccentricity. The evidence is pointing to the imaged object not being massive enough to be the culprit: as the paper notes, the "real" Fomalhaut b may still be out there...

Constraining the Planetary System of Fomalhaut Using High-Resolution ALMA Observations

Proposes a model where the ring is shaped by inner and outer shepherd planets, which would need to be low-mass planets to reproduce the ring.

Quote :

In the massless ring-particle limit, either both planets must be < 3M_Earth, or they must have an extreme mass ratio. The planets do not need to be in resonance. A super-Earth and a Mars-mass planet produce the most narrowly-peaked Gaussian for the radial parent body distribution among the simulations presented here.

Maybe Fomalhaut b is the inner super-Earth ring shepherd?

Quote :

If the scattered optical light observations have detected Fom b, then the candidate could be the innermost shepherd, although there is a discrepancy of ~10 AU between Fom b’s proposed a and the inner shepherd in our models.

http://www.eso.org/public/news/eso1216/



EDIT : sorry... https://solar-flux.forumotion.com/t758p15-fomalhaut-b-orbit-problems#7334

Are the second planet confirmed?

No. And quite honestly the first reported planet is on very shakey ground at the moment.

I've merged the topic with the existing Fomalhaut thread. Also, I've merged the "Spin-Orbit alignment of Fomalhaut b" and "Image of a planet around Fomalhaut" threads to concatenate all the developments on this system.

Direct Imaging Confirmation and Characterization of a Dust-Enshrouded Candidate Exoplanet Orbiting Fomalhaut
http://arxiv.org/abs/1210.6620

Quote :

We present Subaru/IRCS J band data for Fomalhaut and a (re)reduction of archival 2004--2006 HST/ACS data first presented by Kalas et al. (2008). We confirm the existence of a candidate exoplanet, Fomalhaut b, in both the 2004 and 2006 F606W data sets at a high signal-to-noise. Additionally, we confirm the detection at F814W and present a new detection in F435W. Fomalhaut b's space motion may be consistent with it being in an apsidally-aligned, non debris ring-crossing orbit, although new astrometry is required for firmer conclusions. We cannot confirm that Fomalhaut b exhibits 0.7-0.8 mag variability cited as evidence for planet accretion or a semi-transient dust cloud. The new, combined optical SED and IR upper limits confirm that emission identifying Fomalhaut b originates from starlight scattered by small dust, but this dust is most likely associated with a massive body. The Subaru and IRAC/4.5 micron upper limits imply M < 2 Mj, still consistent with the range of Fomalhaut b masses needed to sculpt the disk. Fomalhaut b is very plausibly "a planet identified from direct imaging" even if current images of it do not, strictly speaking, show thermal emission from a directly imaged planet.

Fomalhaut b: Independent Analysis of the Hubble Space Telescope Public Archive Data
http://arxiv.org/abs/1210.6745

Quote :

The nature and even the existence of a putative planet-mass companion ("Fomalhaut b") to Fomalhaut has been debated since 2008. In the present paper we reanalyze the multi-epoch Hubble Space Telescope (HST) optical images on which the discovery claim was based. We confirm that the HST images do reveal an object in orbit around Fomalhaut but the detailed results from our analysis differ in some ways from previous discussions. In particular, we do not confirm flux variability over a two-year interval at 0.6-micron wavelength, we detect Fomalhaut b for the first time at the short wavelength of 0.43microns, we find that the HST image of Fomalhaut b at 0.8m icrons may be extended beyond the PSF, and we cannot determine from our astrometry if Fomalhaut b will cross or not the dust ring. The optical through mid-infrared spectral energy distribution (SED) of Fomalhaut b cannot be explained as due to direct or scattered radiation from a massive planet. We consider two models to explain the SED: (1) a large circumplanetary disk around a massive, but unseen, planet and (2) the aftermath of a collision during the past 100 years of two Kuiper Belt-like objects of radii about 50 km.

One would have imagined that direct imaging is an unambiguous way to confirm a planet...

SpaceRef: New Study Brings a Doubted Exoplanet 'Back from the Dead'

Press release associated with the Currie et al. paper.

Can't wait to see new HST image of Fomalhaut b! I hope there will be something to look at .

It's in the paper.

Nah. I mean this year's photos .

Coronagraphic observations of Fomalhaut at solar system scales
http://arxiv.org/abs/1212.1459

No brown dwarfs or superplanets in the inner system.

more and more mysterious :

http://www.nasa.gov/home/hqnews/2013/jan/HQ_13-005_Hubble_Fomalhaut_Confirmed.html

« …Newly released NASA Hubble Space Telescope images of a vast debris disk encircling the nearby star Fomalhaut and a mysterious planet circling it may provide forensic evidence of a titanic planetary disruption in the system.
Astronomers are surprised to find the debris belt is wider than previously known, spanning a section of space from 14 to nearly 20 billion miles from the star. Even more surprisingly, the latest Hubble images have allowed a team of astronomers to calculate the planet follows an unusual elliptical orbit that carries it on a potentially destructive path through the vast dust ring… »