Young planetary system around HD 163296

http://www.almaobservatory.org/en/press-room/press-releases/1082-alma-finds-compelling-evidence-for-pair-of-infant-planets-around-young-star

ALMA Finds Compelling Evidence for Pair of Infant Planets around Young Star

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) contain compelling evidence that two newborn planets, each about the size of Saturn, are in orbit around a young star known as HD 163296. These planets, which are not yet fully formed, revealed themselves by the dual imprint they left in both the dust and the gas portions of the star’s protoplanetary disk.

The two Saturn-mass protoplanets of HD 163296 have been added to EPE:

http://exoplanet.eu/catalog/hd_163296_b/
http://exoplanet.eu/catalog/hd_163296_c/

I don't understand why many other transiting and non transiting validated planets haven't been added. Updates have turned quite odd at EPE lately.

A Kinematical Detection of Two Jupiter Mass Planets
https://arxiv.org/abs/1805.10290

Quote :

We present the first kinematical detection of embedded protoplanets within a protoplanetary disk. Using archival ALMA observations of HD 163296, we demonstrate a new technique to measure the rotation curves of CO isotopologue emission to sub-percent precision relative to the Keplerian rotation. These rotation curves betray substantial deviations caused by local perturbations in the radial pressure gradient, likely driven by gaps carved in the gas surface density by Jupiter-mass planets. Comparison with hydrodynamic simulations shows excellent agreement with the gas rotation profile when the disk surface density is perturbed by two Jupiter mass planets at 83 au and 137 au. As the rotation of the gas is dependent on the pressure of the total gas component, this method provides a unique probe of the gas surface density profile without incurring significant uncertainties due to gas-to-dust ratios or local chemical abundances which plague other methods. Future analyses combining both methods promise to provide the most accurate and robust measures of embedded planetary mass. Furthermore, this method provides a unique opportunity to explore wide-separation planets beyond the mm continuum edge and to trace the gas pressure profile essential in modelling grain evolution in disks.

A possible third planet may exist but they can't be particularly confident in that at this time.

Also in today's batch of papers:

Pinte et al. "Kinematic evidence for an embedded protoplanet in a circumstellar disc"
https://arxiv.org/abs/1805.10293

They analyse the ALMA data for the same system and come to the conclusion that there is a single 2 Jupiter-mass planet at 260 AU.

Same data, different result

ESO press release :

http://www.eso.org/public/news/eso1818/

ALMA Discovers Trio of Infant Planets around Newborn Star

Two independent teams of astronomers have used ALMA to uncover convincing evidence that three young planets are in orbit around the infant star HD 163296. Using a novel planet-finding technique, the astronomers identified three disturbances in the gas-filled disc around the young star: the strongest evidence yet that newly formed planets are in orbit there. These are considered the first planets to be discovered with ALMA

Multi-epoch Direct Imaging and Time-Variable Scattered Light Morphology of the HD 163296 Protoplanetary Disk
https://arxiv.org/abs/1811.07785

Quote :

We present H-band polarized scattered light imagery and JHK high-contrast spectroscopy of the protoplanetary disk around HD 163296 observed with the HiCIAO and SCExAO/CHARIS instruments at Subaru Observatory. The polarimetric imagery resolve a broken ring structure surrounding HD 163296 that peaks at a distance along the major axis of 0.65 (66 AU) and extends out to 0.98 (100 AU) along the major axis. Our 2011 H-band data exhibit clear axisymmetry, with the NW- and SE- side of the disk exhibiting similar intensities. Our data are clearly different than 2016 epoch H-band observations from VLT/SPHERE that found a strong 2.7x asymmetry between the NW- and SE-side of the disk. Collectively, these results indicate the presence of time variable, non-azimuthally symmetric illumination of the outer disk. Based on our 3D-MCRT modeling of contemporaneous IR spectroscopic and H-band polarized intensity imagery of the system, we suggest that while the system could plausibly host an inclined inner disk component, such a component is unlikely to be responsible for producing the observed time-dependent azimuthal variations in the outer scattered light disk of the system. While our SCExAO/CHARIS data are sensitive enough to recover the planet candidate identified from NIRC2 in the thermal IR, we fail to detect an object with a corresponding JHK brightness estimated from the atmospheric models of Baraffe et al. 2003. This suggests that the candidate is either fainter in JHK bands than model predictions, possibly due to extinction from the disk or atmospheric dust/clouds, or that it is an artifact of the dataset/data processing. Our SCExAO/CHARIS data lower the IR mass limits for planets inferred at larger stellocentric separations; however, these ALMA-predicted protoplanet candidates are currently still consistent with direct imaging constraints.

(emphasis mine)

http://www.inaf.it/en/inaf-news/hd-163296

Giant planets and comets battling in the circumstellar disk around HD 163296

In a study appearing today on The Astrophysical Journal, an INAF-lead team of researchers explored whether the anomalous features in the dust and gas distributions of HD 163296's disk revealed by ALMA's observations could arise from the interaction of the giant planets with a component of the disk previously unaccounted for: the planetesimals

Mesa et al. "Determining mass limits around HD163296 through SPHERE direct imaging data"
https://arxiv.org/abs/1906.05663

No detections but some limits on what could be there.

A new entry

A new planet candidate detected in a dust gap of the disc around HD 163296 through localised kinematic signatures. An observational validation of the Discminer

Quote :

We report the robust detection of coherent, localised deviations from Keplerian rotation possibly associated with the presence of two giant planets embedded in the disc around HD 163296. The analysis is performed using the DISCMINER channel-map modelling framework on 12CO J=2−1 DSHARP data. Not only orbital radius, but also azimuth of the planets are retrieved by our technique. One of the candidate planets, detected at R=94±6 au, ϕ=50±3∘ (P94), is near the centre of one of the gaps in dust continuum emission, and is consistent with a planet mass of 1 MJup. The other planet, located at R=261±4 au, ϕ=57±1∘ (P261), is in the region where a velocity kink was previously observed in 12CO channel maps. Also, we provide a simultaneous description of the height and temperature of the upper and lower emitting surfaces of the disc, and propose the line width as a solid observable to track gas substructure. Using azimuthally averaged line width profiles we detect gas gaps at R=38 au, R=88 au, and R=136 au, closely matching the location of their dust and kinematical counterparts. Furthermore, we observe strong azimuthal asymmetries in line widths around the gas gap at R=88 au, possibly linked to turbulent motions driven by the P94 planet. Our results confirm that the DISCMINER is capable of finding localised, otherwise unseen velocity perturbations thanks to its robust statistical framework, but also that it is well suited for studies of the gas properties and vertical structure of protoplanetary discs.

Two planets at HD 163296

A gap-sharing planet pair shaping the crescent in HD 163296: a disk sculpted by a resonant chain

Quote :

ALMA observations of the disk around HD 163296 have resolved a crescent-shape substructure at around 55 au, inside and off-center from a gap in the dust that extends from 38 au to 62 au. In this work we propose that both the crescent and the dust rings are caused by a compact pair (period ratio ≃4:3) of sub-Saturn-mass planets inside the gap, with the crescent corresponding to dust trapped at the L5 Lagrange point of the outer planet. This interpretation also reproduces well the gap in the gas recently measured from the CO observations, which is shallower than what is expected in a model where the gap is carved by a single planet. Building on previous works arguing for outer planets at ≈86 and ≈137 au, we provide with a global model of the disk that best reproduces the data and show that all four planets may fall into a long resonant chain, with the outer three planets in a 1:2:4 Laplace resonance. We show that this configuration is not only an expected outcome from disk-planet interaction in this system, but it can also help constraining the radial and angular position of the planet candidates using three-body resonances.

Kinematic signatures of a low-mass planet with a moderately inclined orbit in a protoplanetary disk

Quote :

A planet embedded in a protoplanetary disk produces a gap by disk-planet interaction. It also generates velocity perturbation of gas, which can also be observed as deviations from the Keplerian rotation in the channel map of molecular line emission, called kinematic planetary features. These observed signatures provide clues to determine the mass of the planet. We investigated the features induced by the planet with an inclined orbit through three-dimensional hydrodynamic simulations. We found that a smaller planet, with the inclination being ∼10∘ -- 20∘, can produce kinematic features as prominent as those induced by the massive coplanar planet. Despite the kinematic features being similar, the gap is shallower and narrower as compared with the case in which the kinematic features are formed by the coplanar planet. We also found that the kinematic features induced by the inclined planet were fainter for rarer CO isotopologues because the velocity perturbation is weaker at the position closer to the midplane, which was different in the case with a coplanar massive planet. This dependence on the isotopologues is distinguished if the planet has the inclined orbit. We discussed two observed kinematic features in the disk of HD 163296. We concluded that the kink observed at 220 au can be induced by the inclined planet, while the kink at 67 au is consistent to that induced by the coplanar planet.