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 Circumbinary planet(s) at *V4046 Sgr?

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Edasich
dK star
dK star
Edasich


Number of posts : 2288
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

Circumbinary planet(s) at *V4046 Sgr? Empty
PostSubject: Circumbinary planet(s) at *V4046 Sgr?   Circumbinary planet(s) at *V4046 Sgr? Empty25th November 2021, 10:29 am

This young binary has been mentioned several times in years in protoplanetary disk studies and protoplanet searches. Now there are increasingly convincing hints of one or more circumbinary planets imaged within the disk of *V4046 Sgr, as follows

The steady-state hydrodynamics of a long-lived disc: planetary system architecture and prospects of observing a circumplanetary disc shadow in V4046 Sgr

Quote :
Recent imaging of the disc around the V4046Sgr spectroscopic binary revealed concentric regions of dust rings and gaps. The object's proximity and expected equilibrated state due to its old age (>20Myr) make it a superb testbed for hydrodynamical studies in direct comparison to observations. We employ two-dimensional hydrodynamical simulations of gas and multiple dust species to test whether the observed structure conforms with the presence of giant planets embedded in the disc. We then perform radiative transfer calculations of sky images, which we filter for the telescope response for comparison with near-infrared and millimetre observations. We find that the existing data are in excellent agreement with a flared disc and the presence of two giant planets, at 9au and 20au, respectively. The different ring widths are recovered by diffusion-balanced dust trapping within the gas pressure maxima. In our radiative transfer model, the diffusion in vertical direction is reduced in comparison to the radial value by a factor of five to recover the spectral energy distribution. Further, we report a previously unaddressed, azimuthally-confined intensity decrement on the bright inner ring in the near-infrared scattered light observation. Our model shows that this decrement can be explained by a shadow cast by a circumplanetary disc around the same giant planet that creates the inner cavity in the hydrodynamical simulations. We examine the shape of the intensity indentation and discuss the potential characterisation of a giant planet and its associated disc by its projected shadow in scattered light observations.

Emphasis mine.
Another paired paper

High-resolution ALMA observations of V4046 Sgr: a circumbinary disc with a thin ring

Quote :
The nearby V4046 Sgr spectroscopic binary hosts a gas-rich disc known for its wide cavity and dusty ring. We present high resolution (∼20 mas or 1.4 au) ALMA observations of the 1.3mm continuum of V4046 Sgr which, combined with SPHERE--IRDIS polarised images and a well-sampled spectral energy distribution (SED), allow us to propose a physical model using radiative transfer (RT) predictions. The ALMA data reveal a thin ring at a radius of 13.15±0.42 au (Ring13), with a radial width of 2.46±0.56 au. Ring13 is surrounded by a ∼10 au-wide gap, and it is flanked by a mm-bright outer ring (Ring24) with a sharp inner edge at 24 au. Between 25 and ∼35 au the brightness of Ring24 is relatively flat and then breaks into a steep tail that reaches out to ∼60 au. In addition, central emission is detected close to the star which we interpret as a tight circumbinary ring made of dust grains with a lower size limit of 0.8 mm at 1.1 au. In order to reproduce the SED, the model also requires an inner ring at ∼5 au (Ring5) composed mainly of small dust grains, hiding under the IRDIS coronagraph, and surrounding the inner circumbinary disc. The surprisingly thin Ring13 is nonetheless roughly 10 times wider than its expected vertical extent. The strong near-far disc asymmetry at 1.65 μm points at a very forward-scattering phase function and requires grain radii of no less than 0.4 μm.
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Edasich
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dK star
Edasich


Number of posts : 2288
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

Circumbinary planet(s) at *V4046 Sgr? Empty
PostSubject: Re: Circumbinary planet(s) at *V4046 Sgr?   Circumbinary planet(s) at *V4046 Sgr? Empty30th November 2021, 12:07 pm

I'm not sure whether post this here or in a dedicated thread possibly concerning all about "planets in protoplanetary disks", imaged and/or modelled, because this system is much like *V4046 Sgr in several aspects.

The protoplanetary disc around HD 169142: circumstellar or circumbinary?
Quote :
Stellar binaries represent a substantial fraction of stellar systems, especially among young stellar objects. Accordingly, binaries play an important role in setting the architecture of a large number of protoplanetary discs. Binaries in coplanar and polar orientations with respect to the circumbinary disc are stable configurations and could induce non-axisymmetric structures in the dust and gas distributions. In this work, we suggest that the structures shown in the central region of the protoplanetary disc HD 169142 are produced by the presence of an inner stellar binary and a circumbinary (P-type) planet. We find that a companion with a mass-ratio of 0.1, semi-major axis of 9.9 au, eccentricity of 0.2, and inclination of 90°, together with a 2 Jupiter Mass coplanar planet on a circular orbit at 45 au reproduce the structures at the innermost ring observed at 1.3 mm and the shape of spiral features in scattered light observations. The model predicts changes in the disc's dust structure, and star's astrometric parameters, which would allow testing its veracity by monitoring this system over the next 20 years.

The dedicated thread options sounds better and more practical and allows to merge several entries concerning exoplanets within proplyds (e.g. KR Mus, CU Cha, CQ Tau...) unless single discovery is so exceptional to deserve a thread of its own.
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Edasich
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Edasich


Number of posts : 2288
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

Circumbinary planet(s) at *V4046 Sgr? Empty
PostSubject: Re: Circumbinary planet(s) at *V4046 Sgr?   Circumbinary planet(s) at *V4046 Sgr? Empty26th January 2022, 11:18 am

Being mentioned this system, the thread bump is necessary (scroll down the page to find full-text PDF)

X-Shooter characterization of very wide companion candidates to young stars with planets and disks
Quote :
Discovering wide companions of stellar systems allows us to constrain the dynamical environment and age of the latter. We studied four probable wide companions of four different stellar systems. The candidates were selected mainly based on their similar kinematic properties to the central star using Gaia DR2. The central stars are V4046 Sgr, HIP 74865, HIP 65426, and HIP 73145, and their probable wide companions are 2MASS J18152222-3249329, 2MASS J15174874-3028484, 2MASS J13242119-5129503, and 2MASS J14571503-3543505 respectively. V4046 Sgr is a member of β-Pictoris Moving Group while the rest of the stellar systems are acknowledged as members of the Scorpius-Centaurus association. The selected stellar systems are particularly interesting because all of them are already known to possess a low-mass companion and/or a spatially resolved disk. Identifying wider companions of these stars can improve their eligibility as benchmarks for understanding the formation channels of various triple systems, and can help us to determine the orbits of their possibly undiscovered inner, wider companions in case of higher multiplicity. By analyzing the X-shooter spectra of the wide companion candidates of these stars, we obtained their stellar parameters and determined their ages. We find that 2MASS J15174874-3028484 (0.11 M⊙, 7.4 ± 0.5 Myr), an already recognized pre-main sequence (PMS) member of Scorpius-Centaurus association, is a highly probable wide companion of HIP 74865. 2MASS J13242119-5129503 (0.04 M⊙, 16 ± 2.2 Myr) is ruled out as a plausible wide companion of HIP 65426, but confirmed to be a new sub-stellar member of the Scorpius-Centaurus association. 2MASS J14571503-3543505 (0.02 M⊙, 17.75 ± 4.15 Myr) is a probable sub-stellar member of the same association, but we cannot confirm whether or not it is gravitationally bound to HIP 73145. 2MASS J18152222-3249329 (0.3 M⊙, older than 150 Myr) is determined to be a mildly active main sequence star, much older than members of β-Pictoris Moving Group, and unbound to V4046 Sgr despite their similar kinematic features. PMS wide companions such as 2MASS J15174874-3028484 might have formed through cascade fragmentation of their natal molecular core, hinting at high multiplicity in shorter separations which can be confirmed with future observations.

Not comoving with *V4046 Sgr but certainly member of the same association and (almost) certainly substellar. By the way there is a possible substellar companion to HIP 73145 and some stand-alone object missing from the "rogue planets" list.

Anyway a closer to look to first post in the thread about *V4046 Sgr should be considered, because it seems there is a discovery claim of two imaged planets around it or something very close to this.
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Led_Zep
SuperJovian
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Led_Zep


Number of posts : 721
Location : France
Registration date : 2011-09-09

Circumbinary planet(s) at *V4046 Sgr? Empty
PostSubject: Re: Circumbinary planet(s) at *V4046 Sgr?   Circumbinary planet(s) at *V4046 Sgr? Empty24th April 2023, 7:53 am

https://www.eso.org/public/france/videos/potw2317a/

A new planet is born
This Picture of the Week shows a newly-formed planet with a mass similar to Jupiter’s orbiting the star HD 169142. The star has a disc around it, and as the protoplanet moves it carves a circular gap in the disc, as seen in the first image
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Circumbinary planet(s) at *V4046 Sgr? Empty
PostSubject: Re: Circumbinary planet(s) at *V4046 Sgr?   Circumbinary planet(s) at *V4046 Sgr? Empty

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