Gas Accretion within the Dust Cavity in AB Aur*

Rivière-Marichalar, P.; Fuente, A.; Neri, R.; Treviño-Morales, S. P.; Agúndez, M.; Bachiller, R.

doi:10.3847/2041-8213/ab289d

Cited by 9 publications

(29 citation statements)

References 37 publications

(63 reference statements)

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“…Most species depicted ring-like emission co-spatial with the dust ring with a minimum towards the central dust gap, except 12 CO and HCO + . The higher angular resolution image of the HCO + 3→2 line reported by Rivière-Marichalar et al (2019) shows that within the dust cavity the HCO + emission is formed by a compact source towards the stellar position and at least one filament connecting the compact source with the outer ring. We concluded that the filamentary structure could be tracing an accretion flow from the outer ring into the inner disk.…”

Section: Introductionmentioning

confidence: 89%

“…3.1). In addition to the data presented, we have included the profiles of the HCO + 3→2 and HCN 3→2 maps reported by Rivière-Marichalar et al (2019).…”

Section: Chemical Segregationmentioning

confidence: 99%

“…We estimated the column densities of CO, H 2 CO, and SO assuming LTE, and the mean kinetic temperature derived from the H 2 CO line ratios. We also computed column density maps for HCO + and HCN using the data published by Rivière-Marichalar et al (2019), and following the same procedure. Table 3 summarizes the results for the different species.…”

Section: Molecular Column Densities and Abundancesmentioning

confidence: 99%

“…So far, a few molecular species have been detected in AB Aur, including CO, SO, HCO + , HCN, and H 2 CO (Schreyer et al 2008;Piétu et al 2005;Tang et al 2012Tang et al , 2017Fuente et al 2010;Pacheco-Vázquez et al 2015Rivière-Marichalar et al 2019). It is remarkable that the first detection of SO in a protoplanetary disk was reported towards AB Aur (Fuente et al 2010;Pacheco-Vázquez et al 2015.…”

Section: Introductionmentioning

confidence: 99%

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AB Aur, a Rosetta stone for studies of planet formation

Riviére-Marichalar

Fuente

Gal

et al. 2020

A&A

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Context. AB Aur is a Herbig Ae star that hosts a prototypical transition disk. The disk shows a plethora of features connected with planet formation mechanisms, such as spiral arms, dust cavities, and dust traps. Understanding the physical and chemical characteristics of these features is crucial to advancing our knowledge of the planet formation processes. Aims. We aim to characterize the gaseous disk around the Herbig Ae star AB Aur. A complete spectroscopic study was performed using NOEMA to determine the physical and chemical conditions with high spatial resolution. Methods. We present new NOrthern Extended Millimeter Array (NOEMA) interferometric observations of the continuum and 12CO, 13CO, C18O, H2CO, and SO lines obtained at high resolution. We used the integrated intensity maps and stacked spectra to derive reliable estimates of the disk temperature. By combining our 13CO and C18O observations, we computed the gas-to-dust ratio along the disk. We also derived column density maps for the different species and used them to compute abundance maps. The results of our observations were compared with a set of Nautilus astrochemical models to obtain insight into the disk properties. Results. We detected continuum emission in a ring that extends from 0.6′′ to ~2.0′′, peaking at 0.97′′ and with a strong azimuthal asymmetry. The molecules observed show different spatial distributions, and the peaks of the distributions are not correlated with the binding energy. Using H2CO and SO lines, we derived a mean disk temperature of 39 K. We derived a gas-to-dust ratio that ranges from 10 to 40 along the disk. Abundance with respect to 13CO for SO (~2 × 10−4) is almost one order of magnitude greater than the value derived for H2CO (1.6 × 10−5). The comparison with Nautilus models favors a disk with a low gas-to-dust ratio (40) and prominent sulfur depletion. Conclusions. From a very complete spectroscopic study of the prototypical disk around AB Aur, we derived, for the first time, the gas temperature and the gas-to-dust ratio along the disk, providing information that is essential to constraining hydrodynamical simulations. Moreover, we explored the gas chemistry and, in particular, the sulfur depletion. The derived sulfur depletion is dependent on the assumed C/O ratio. Our data are better explained with C/O ~ 0.7 and S/H = 8 × 10−8.

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Section: Introductionmentioning

confidence: 89%

“…3.1). In addition to the data presented, we have included the profiles of the HCO + 3→2 and HCN 3→2 maps reported by Rivière-Marichalar et al (2019).…”

Section: Chemical Segregationmentioning

confidence: 99%

Section: Molecular Column Densities and Abundancesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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AB Aur, a Rosetta stone for studies of planet formation

Riviére-Marichalar

Fuente

Gal

et al. 2020

A&A

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“…Figure 9 shows a comparison between the observed dust continuum emission at 1.3 mm (Tang et al 2012) and the dust distribution in e50-i60, where the dust over-density is seen as a large clump due to beaming effects. In addition, Rivière-Marichalar et al (2019) very recently reported the observation of clumps in HCN -a good tracer of cold and dense gas -around the inner edge of the disc. This supports the idea that the dusty clumps might be real.…”

Section: The Ab Aurigae Systemmentioning

confidence: 99%

Dusty clumps in circumbinary discs

Poblete

Cuello

Cuadra

2019

Monthly Notices of the Royal Astronomical Society

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Recent observations have revealed that protoplanetary discs often exhibit cavities and azimuthal asymmetries such as dust traps and clumps. The presence of a stellar binary system in the inner disc regions has been proposed to explain the formation of these structures. Here, we study the dust and gas dynamics in circumbinary discs around eccentric and inclined binaries. This is done through two-fluid simulations of circumbinary discs, considering different values of the binary eccentricity and inclination. We find that two kinds of dust structures can form in the disc: a single horseshoe-shaped clump, on top of a similar gaseous over-density; or numerous clumps, distributed along the inner disc rim. The latter features form through the complex interplay between the dust particles and the gaseous spirals caused by the binary. All these clumps survive between one and several tens of orbital periods at the feature location. We show that their evolution strongly depends on the gas-dust coupling and the binary parameters. Interestingly, these asymmetric features could in principle be used to infer or constrain the orbital parameters of a stellar companion -potentially unseen -inside the inner disc cavity. Finally, we apply our findings to the disc around AB Aurigae.

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Possible evidence of ongoing planet formation in AB Aurigae

Boccaletti

Folco

Pantin

et al. 2020

A&A

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Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain to be tested through observations. Aims. With the recent discovery, using ALMA, of two gaseous spiral arms inside the ∼120 au cavity and connected to dusty spirals, the famous protoplanetary disk around AB Aurigae presents a strong incentive for investigating the mechanisms that lead to giant planet formation. A candidate protoplanet located inside a spiral arm has already been claimed in an earlier study based on the same ALMA data. Methods. We used SPHERE at the Very Large Telescope to perform near-infrared high-contrast imaging of AB Aur in polarized and unpolarized light in order to study the morphology of the disk and search for signs of planet formation. Results. SPHERE has delivered the deepest images ever obtained for AB Aur in scattered light. Among the many structures that are yet to be understood, we identified not only the inner spiral arms, but we also resolved a feature in the form of a twist in the eastern spiral at a separation of about 30 au. The twist of the spiral is perfectly reproduced with a planet-driven density wave model when projection effects are accounted for. We measured an azimuthal displacement with respect to the counterpart of this feature in the ALMA data, which is consistent with Keplerian motion on a 4 yr baseline. Another point sxce is detected near the edge of the inner ring, which is likely the result of scattering as opposed to the direct emission from a planet photosphere. We tentatively derived mass constraints for these two features. Conclusions. The twist and its apparent orbital motion could well be the first direct evidence of a connection between a protoplanet candidate and its manifestation as a spiral imprinted in the gas and dust distributions.

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Gas Accretion within the Dust Cavity in AB Aur*

Cited by 9 publications

References 37 publications

AB Aur, a Rosetta stone for studies of planet formation

AB Aur, a Rosetta stone for studies of planet formation

Dusty clumps in circumbinary discs

Possible evidence of ongoing planet formation in AB Aurigae

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