Radio Continuum Components from Dust in the MWC758 Protoplanetary - - PowerPoint PPT Presentation

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Radio Continuum Components from Dust in the MWC758 Protoplanetary - - PowerPoint PPT Presentation

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Radio Continuum Components from Dust in the MWC758 Protoplanetary Disk Simon Casassus 1,2 , Matas Vidal , Thiem Hoang et al. 1.Universidad de Chile 2. M illennium A lma D isk nucleus http://madnucleus.com TagKASI conference 2018 Outline 1.

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SLIDE 1

Radio Continuum Components from Dust in the MWC758 Protoplanetary Disk

1.Universidad de Chile 2.Millennium Alma Disk nucleus

Simon Casassus1,2, Matías Vidal, Thiem Hoang et al.

http://madnucleus.com TagKASI conference 2018

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SLIDE 2

Outline

  • 1. Lopsided rings
  • 2. Dust trapping in MWC758
  • 3. Excess microwave emission?
  • 4. Summary
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SLIDE 3

Outline

  • 1. Lopsided rings
  • 2. Dust trapping in MWC758
  • 3. Excess microwave emission?
  • 4. Summary
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SLIDE 4

Lopsided rings

  • HD142527: Factor of 30 asymmetry along ~140AU ring (Ohashi 2008,

Casassus+ 2013 JAO PR, Muto+ 2015, Boehler+ 2017)

  • IRS48: Factor of 100 asymmetry along ~80AU

ring (van der Marel+ 2013 JAO PR, van der Marel+ 2016)

  • Interestingly, both cavities in HD142527 and

IRS48 are filled with residual 12CO emission

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SLIDE 5
  • HD135344B (Cazolletti + 2018)

Examples of milder contrasts

  • SR21 (van der Marel+ 2016)
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SLIDE 6

Radial dust trapping

super-Keplerian gas velocity sub-Keplerian gas velocity

vr,dust vr,dust

∂P ∂r = 0 ⇒ vφ ,gas = vk

P(r) r

  • Pinilla, Youdin 2017
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SLIDE 7

Azimuthal dust trapping

  • Azimuthal dust trapping in anticyclonic vortices proposed in the 90s as a

pathway for efficient core accretion (Barge & Sommeira 1995)

  • The extreme lopsidedness of HD142527 and IRS48 are suggestive
  • f dust trapping in a mild pressure maximum. However, the

predicted grain size segregation is not yet observed.

  • Trapping in a generic gas background (Birnstiel+ 2013):
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SLIDE 8

Outline

  • 1. Lopsided rings
  • 2. Dust trapping in MWC758
  • 3. Excess microwave emission?
  • 4. Summary
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SLIDE 9

Dust trapping in MWC 758

  • MWC758 (ALMA blue,

VLA red Marino+ 2015)

  • ALMA B7 345GHz (Boehler+ 2018)
  • ALMA B7 345GHz (reprocessing of

data from Dong+ 2018)

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SLIDE 10

New VLA observations of MWC758

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SLIDE 11

New VLA observations of MWC758

ALMA deconvolution VLA no star

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SLIDE 12

Polar maps and azimuthal profiles

  • Polar maps.


Grey: VLA, no star
 Black contours: B7

  • Azimuthal profiles
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SLIDE 13

Steady state dust trapping HV (a) = H f (χ) s 1 (S(a) + 1),

  • Lyra & Lin (2013) prescriptions

account for the observed trends

  • Gas background ~ elliptical

Gaussian, with aspect ratio 𝝍

  • Grain optical properties from 


Kataoka+ (2014)

S(a) = π 2 aρ∙ αΣg

  • Vortex scale length:
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SLIDE 14

Steady state dust trapping

  • Cold vortex, T~24K
  • Elongated vortex, 𝝍 ~ 14
  • Compact grains, f~0.2
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SLIDE 15

Dust+gas hydro for MWC758

  • 100
  • 50

50 100 x [au]

  • 100
  • 50

50 100 y [au]

  • 1
1 2 1 2 3 4
  • 1

1 2 Perturbed Gas density at 1323 orbits

  • 100
  • 50

50 100 x [au]

  • 100
  • 50
50 100 y [au]
  • 1
1 2 1 2 3 4
  • 1

1 2 Perturbed Gas density at 1323 orbits

1 2 3 4 0.002 0.004 0.006 0.008 0.010

10-5 10-4 10-3 10-2 Particles size [m]

  • Dust FARGO ADSG (Baruteau+ 2018, submitted)
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SLIDE 16

Dust+gas hydro for MWC758

  • Comparison with data (Baruteau+ 2018, submitted)

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative RA [arcsec]

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative DEC [arcsec] λ = 0.87 mm

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative RA [arcsec]

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative DEC [arcsec] 342 GHz

Clump 1 Clump 2

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative RA [arcsec]

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative DEC [arcsec] λ = 9.0 mm

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative RA [arcsec]

−0.6 −0.4 −0.2 0.0 0.2 0.4 0.6

Relative DEC [arcsec] 33 GHz

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SLIDE 17

Dust trapping in MWC 758

  • Observations + Lyra & Lin (2013) prescriptions require a very

elongated vortex, with 𝝍 ~ 15

  • Supported by dust+gas hydro.
  • Good potential to extract physical conditions from multi-

frequency observations of lopsided transition disks.

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SLIDE 18

Outline

  • 1. Lopsided rings
  • 2. Dust trapping in MWC758
  • 3. Excess microwave emission?
  • 4. Summary
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SLIDE 19

Excess Microwave Emission in MWC758

???

  • Grey, red contours: 


VLA, no star, no Clump1, smoothed to ALMA natural beam

  • Black contours: 


ALMA 345GHz, natural weights

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SLIDE 20

Excess Microwave Emission in MWC758

  • Tentative interpretation: electric dipole radiation from spinning dust

emission due to Very Small Grains (VSGs, a~1nm).

  • VSGs are well coupled with the gas.
  • Predict EME map given physical conditions in the gas background
  • f a parametric model that fits SED +
  • Calculate spinning dust emissivities with code from Hoang+ (2018)
  • Unknown VSG column-> scale to `Feature 3’.
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SLIDE 21

Excess Microwave Emission in MWC758

  • Hoang+ (2018)
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SLIDE 22

Excess Microwave Emission in MWC758

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SLIDE 23

Summary: radio components from dust in MWC758

  • Thermal dust emission:
  • MWC758 = good example for dust

trapping in a vortex.

  • VLA/ALMA data + Lyra-Lin

prescriptions allow estimates of physical conditions.

  • Excess Microwave Emission:
  • Diffuse 33GHz signal, more

extended than Rayleigh-Jeans tail

  • f the sub-mm-emitting dust.
  • Diffuse emission follows spinning

dust maps based on gas background.

  • Confirmation of spinning dust

pending spectral trends (VLA proposal 2019A)