Four new planetesimals around typical and pre-main-sequence  stars (PLATYPUS) debris discs at 8.8 mm

Norfolk, Brodie J.; Maddison, Sarah; Marshall, Jonathan P.; Kennedy, Grant M.; Duchêne, Gaspard; Wilner, David J.; Pinte, C.; Moór, A.; Matthews, Brenda C.; Ábrahám, P.; Kóspál, Á.; Marel, Nienke van der

doi:10.1093/mnras/stab1901

Cited by 7 publications

(4 citation statements)

References 105 publications

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“…Overall, Figure 5 shows that the dust temperature is unlikely to be higher than 60K, and that for dust temperatures above 10K the disc fractional luminosity is greater than about 10 −4 . We can also see that our models for the disc of GSC 07396-00759 share the space occu-pied by other M-dwarf discs, namely TWA 7 (Bayo et al 2019), CPD-72 2713 (Moór et al 2020;Tanner et al 2020;Norfolk et al 2021), AU Mic and Fomalhaut C (Kennedy et al 2013;Cronin-Coltsmann et al 2021), with a temperature ∼10-50 K and a blackbody radius ∼10-200 au. However, assuming that all of the dust colocates precisely at the best-fitting ALMA radius we can narrow the probable range occupied by our models with our knowledge of the disc's observed radius which sets a limit on the blackbody temperature in the disc.…”

Section: Flux Density Distribution and Fractional Luminosity Modellingsupporting

confidence: 56%

ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin

Cronin-Coltsmann,

Kennedy,

Adam

et al. 2022

Preprint

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We present new ALMA Band 7 observations of the edge-on debris disc around the M1V star GSC 07396-00759. At ∼ 20 Myr old and in the 𝛽 Pictoris Moving Group along with AU Mic, GSC 07396-00759 joins it in the handful of low mass M-dwarf discs to be resolved in the sub-mm. With previous VLT/SPHERE scattered light observations we present a multi-wavelength view of the dust distribution within the system under the effects of stellar wind forces. We find the mm dust grains to be well described by a Gaussian torus at 70 au with a FWHM of 48 au and we do not detect the presence of CO in the system. Our ALMA model radius is significantly smaller than the radius derived from polarimetric scattered light observations, implying complex behaviour in the scattering phase function. The brightness asymmetry in the disc observed in scattered light is not recovered in the ALMA observations, implying that the physical mechanism only affects smaller grain sizes. High resolution follow-up observations of the system would allow investigation into its unique dust features as well as provide a true coeval comparison for its smaller sibling AU Mic, singularly well observed amongst M-dwarfs systems.

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Section: Flux Density Distribution and Fractional Luminosity Modellingsupporting

confidence: 56%

ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin

Cronin-Coltsmann,

Kennedy,

Adam

et al. 2022

Preprint

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“…The power-law index for grain-size distribution, q, has been inferred via modeling for many debris disks beyond our own solar system (e.g., Löhne et al 2012;Ricci et al 2015;MacGregor et al 2016;Marshall et al 2017;White et al 2018;Hengst et al 2020;Arnold et al 2022;Norfolk et al 2021); nearly all of these systems are consistent with the theoretical steady-state grain-size distribution index q = 3.5 derived by Dohnanyi (1969). Generally, a velocity dispersion of 1 km s -1 is prescribed to all bodies within the Kuiper Belt (Leinhardt et al 2008), which suggests p = 0 locally (as assumed by Dohnanyi 1969); it is important to note that nonnegligible differences in collisional velocities have been measured in various dynamical populations of Kuiper Belt objects (KBOs; e.g., Abedin et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Multiwavelength Vertical Structure in the AU Mic Debris Disk: Characterizing the Collisional Cascade

Vizgan

Hughes

Carter

et al. 2022

ApJ

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Debris disks are scaled-up analogs of the Kuiper Belt in which dust is generated by collisions between planetesimals. In the collisional cascade model of debris disks, the dust lost to radiation pressure and winds is constantly replenished by grinding collisions between planetesimals. The model assumes that collisions are destructive and involve large velocities; this assumption has not been tested beyond our solar system. We present 0.″25 (≈2.4 au) resolution observations of the λ = 450 μm dust continuum emission from the debris disk around the nearby M dwarf AU Microscopii with the Atacama Large Millimeter/submillimeter Array. We use parametric models to describe the disk structure, and a Monte Carlo Markov Chain (MCMC) algorithm to explore the posterior distributions of the model parameters; we fit the structure of the disk to both our data and archival λ = 1.3 mm data (Daley et al. 2019), from which we obtain two aspect ratio measurements at 1.3 mm (h 1300 = 0.025 − 0.002 + 0.008 ) and at 450 μm (h 450 = 0.019 − 0.001 + 0.006 ), as well as the grain-size distribution index q = 3.03 ± 0.02. Contextualizing our aspect ratio measurements within the modeling framework laid out in Pan & Schlichting (2012), we derive a power-law index of velocity dispersion as a function of grain size p = 0.28 ± 0.06 for the AU Mic debris disk. This result implies that smaller bodies are more easily disrupted than larger bodies by collisions, which is inconsistent with the strength regime usually assumed for such small bodies. Possible explanations for this discrepancy are discussed.

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“…We calculate the sub-millimetre slope of the dust emission for HD 16743's disc to have an exponent of 3.72 ± 0.03, significantly steeper than the oft-assumed steady state collisional cascade of 3.5 (Dohnanyi 1969), and the bulk of debris disc measurements 3.3 (MacGregor et al 2016;Marshall et al 2017;Norfolk et al 2021). Comparison with collisional models suggests the measured slope is consistent with the dust originating from collisions between bodies held together by their rigid strength (Pan & Schlichting 2012;Gáspár et al 2012).…”

Section: Discussionmentioning

confidence: 89%

Stirred but not shaken: a multiwavelength view of HD 16743’s debris disc

Marshall

Milli

Choquet

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Planetesimals – asteroids and comets – are the building blocks of planets in protoplanetary discs and the source of dust, ice and gas in debris discs. Along with planets they comprise the left-over material after star formation that constitutes a planetary system. Planets influence the dynamics of planetesimals, sculpting the orbits of debris belts to produce asymmetries or gaps. We can constrain the architecture of planetary systems, and infer the presence of unseen planetary companions, by high spatial resolution imaging of debris discs. HD 16743 is a relatively young F-type star that hosts a bright edge-on debris disc. Based on far-infrared Herschel observations its disc was thought to be stirred by a planetary companion. Here we present the first spatially resolved observations at near-infrared and millimetre wavelengths with HST and ALMA, revealing the disc to be highly inclined at $87{_{.}^{\circ}} 3~^{+1{_{.}^{\circ}} 9}_{-2{_{.}^{\circ}} 5}$ with a radial extent of 157.7$^{+2.6}_{-1.5}$ au and a FWHM of 79.4$^{+8.1}_{-7.8}$ au (ΔR/R = 0.5). The vertical scale height of the disc is 0.13 ± 0.02, significantly greater than typically assumed unstirred value of 0.05, and could be indicative of stirring of the dust-producing planetesimals within the disc by bodies at least a few times the mass of Pluto up to 18.3 M⊕ in the single object limit.

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Four new planetesimals around typical and pre-main-sequence stars (PLATYPUS) debris discs at 8.8 mm

Cited by 7 publications

References 105 publications

ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin

ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin

Multiwavelength Vertical Structure in the AU Mic Debris Disk: Characterizing the Collisional Cascade

Stirred but not shaken: a multiwavelength view of HD 16743’s debris disc

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