9-10 Aprile 2015 - Osservatorio Astronomico di Capodimonte JEDI Meeting 9-10 Aprile 2015 - Osservatorio Astronomico di Capodimonte ALMA/JVLA observations of the dust properties across the CO snowline in HD 163296 G.Guidi, L.Testi, M.Tazzari Greta Guidi PhD student at INAF Arcetri/Università degli Studi di Firenze Supv. L. Testi

Dust grains: the first step toward planet formation Continuum emission from IR to millimeter comes from the dust: [van Dishoeck+ 2014] Grains larger than a few cm cannot be detected!

Resolving the CO snowline in a disk with ALMA: HD 163296 Herbig Ae star Age ~ 5 Myr M*=2,3 M☉ T*= 9500 K L=36 L☉ d=122 pc Mdisk~ 0,1 M☉ [Qi et al. 2013] ALMA 835 μm [TWHyd, Qi et al. 2013] [Mathews et al. 2013] Maybe DCO+ not the better tracer: N2H+ gives a CO snowline for HD 163296 at 100 AU ~ 0.8’’ [Qi 2015 in preparation] H3+ + HD ⇔ H2D+ + H2+ ΔE H2D+ + CO → DCO+ Emission ring of DCO+ : 95-195 AU CO condensation temperature: 19 K → 155 AU ~ 1,3’’

Grain growth across the snowline [van Dishoeck 2014]

More compact emission at longer wavelengths Observations Beam 0.57’’x0.37’’ ~ 60AU Beam 0.74’’x0.60’’ ~ 85AU Beam 0.13’’x0.08’’ ~ 15AU Free-free electron emission becomes a non-negligible contribution at wavelengths ≳ 7 mm More compact emission at longer wavelengths

Radial profiles of spectral index in the disk mid plane 850 μm - 1.3 mm 850 μm - 9 mm Hypothesis: Rayleigh-Jeans regime + optically thin emission

Radial profiles of spectral index in the disk mid plane 850 μm - 1.3 mm 850 μm - 9 mm

Dust emission reveals non-homogeneous features in the disk Flux density radial profile Residuals observations-model [Contours at 3,6,12,24,48 σ] Excess emission near the CO Snowline

Dust emission reveals non-homogeneous features in the disk Major axis [Polarized light contrast from Garufi et al. 2014] [Garufi et al. 2014] Polarized light shows a ring structure at ~0.6” -1”(70-120 AU)

The excess emission is not resolved at 1.3 mm? ALMA Band 6 (1.3 mm) ALMA Band 7 (0.85 mm) Beam 0.74”x0.60” Beam 0.74”x0.60”

Further developments ALMA Cycle 3: high angular resolution/high signal to noise in Band 3 Measurement of the spectral index β(850 μm-3 mm) JVLA K, X, C Bands (1.3 cm, 3 cm, 6 cm) Resolve electrons free free emission In the future… ALMA Band 2 (80GHz) and Band 1 (40GHz) β(850 μm-7 mm) New facilities with high signal to noise and high angular resolution in the range 35 GHz - 350GHz + Improvement of disk models with radial dependent parameters More detailed study of the radial properties of dust and grain growth

Thank you!