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

Radio Continuum Components from Dust in the MWC758 Protoplanetary Disk Simon Casassus 1,2 , Matías 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. Lopsided rings 2. Dust trapping in MWC758 3. Excess microwave emission? 4. Summary

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

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

Examples of milder contrasts • HD135344B (Cazolletti + 2018) • SR21 (van der Marel+ 2016)

Radial dust trapping P ( r ) ∂ P ∂ r = 0 ⇒ v φ , gas = v k super-Keplerian sub-Keplerian gas velocity gas velocity v r , dust v r , dust r Pinilla, Youdin 2017 •

Azimuthal dust trapping • Azimuthal dust trapping in anticyclonic vortices proposed in the 90s as a pathway for e ffi cient core accretion (Barge & Sommeira 1995) • The extreme lopsidedness of HD142527 and IRS48 are suggestive of 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):

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

Dust trapping in MWC 758 • MWC758 (ALMA blue, VLA red Marino+ 2015) • ALMA B7 345GHz (reprocessing of data from Dong+ 2018) • ALMA B7 345GHz (Boehler+ 2018)

New VLA observations of MWC758

New VLA observations of MWC758 ALMA deconvolution VLA no star

Polar maps and azimuthal profiles • Polar maps. 
 Grey: VLA, no star 
 Black contours: B7 • Azimuthal profiles

Steady state dust trapping • Lyra & Lin (2013) prescriptions account for the observed trends • Gas background ~ elliptical Gaussian, with aspect ratio 𝝍 • Grain optical properties from 
 Kataoka+ (2014) • Vortex scale length: s H 1 H V ( a ) = ( S ( a ) + 1 ) , f ( χ ) a ρ ∙ S ( a ) = π 2 α Σ g

Steady state dust trapping • Cold vortex, T~24K • Elongated vortex, 𝝍 ~ 14 • Compact grains, f~0.2

Dust+gas hydro for MWC758 Perturbed Gas density at 1323 orbits Perturbed Gas density at 1323 orbits -1 0 1 2 -1 0 1 2 4 4 3 3 2 2 1 1 0 -1 0 1 2 0 -1 0 1 2 10 -2 0.010 100 100 0.008 50 10 -3 50 Particles size [m] 0.006 y [au] 0 0 y [au] 0.004 10 -4 -50 -50 0.002 -100 -100 10 -5 0 1 2 3 4 -100 -50 0 50 100 -100 -50 0 50 100 x [au] x [au] • Dust FARGO ADSG (Baruteau+ 2018, submitted)

Dust+gas hydro for MWC758 λ = 0 . 87 mm 342 GHz Clump 1 0 . 6 0 . 6 0 . 4 0 . 4 Relative DEC [arcsec] Relative DEC [arcsec] 0 . 2 0 . 2 0 . 0 0 . 0 − 0 . 2 − 0 . 2 − 0 . 4 − 0 . 4 Clump 2 − 0 . 6 − 0 . 6 0 . 6 0 . 4 0 . 2 0 . 0 − 0 . 2 − 0 . 4 − 0 . 6 0 . 6 0 . 4 0 . 2 0 . 0 − 0 . 2 − 0 . 4 − 0 . 6 Relative RA [arcsec] Relative RA [arcsec] λ = 9 . 0 mm 33 GHz 0 . 6 0 . 6 0 . 4 0 . 4 Relative DEC [arcsec] Relative DEC [arcsec] 0 . 2 0 . 2 0 . 0 0 . 0 − 0 . 2 − 0 . 2 − 0 . 4 − 0 . 4 − 0 . 6 − 0 . 6 0 . 6 0 . 4 0 . 2 0 . 0 − 0 . 2 − 0 . 4 − 0 . 6 0 . 6 0 . 4 0 . 2 0 . 0 − 0 . 2 − 0 . 4 − 0 . 6 Relative RA [arcsec] Relative RA [arcsec] • Comparison with data (Baruteau+ 2018, submitted)

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.

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

Excess Microwave Emission in MWC758 ??? • Grey, red contours: 
 VLA, no star, no Clump1, smoothed to ALMA natural beam • Black contours: 
 ALMA 345GHz, natural weights

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 of a parametric model that fits SED + • Calculate spinning dust emissivities with code from Hoang+ (2018) • Unknown VSG column-> scale to `Feature 3’.

Excess Microwave Emission in MWC758 • Hoang+ (2018)

Excess Microwave Emission in MWC758

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: • Di ff use 33GHz signal, more extended than Rayleigh-Jeans tail of the sub-mm-emitting dust. • Di ff use emission follows spinning dust maps based on gas background. • Confirmation of spinning dust pending spectral trends (VLA proposal 2019A)