HD Transition Disk Herbig Ae/Be stars 2014

Transcription

1 a b HD Transition Disk Herbig Ae/Be stars 2014

2 HD ALMA results by Sebastián Pérez Simon Casassus Valentin Christiaens Francois Ménard also with Gerrit van der Plas, Pablo Román, Christian Flores, and de Chile / MAD

3 Talk Overview 1) HD basics and introduction 2) ALMA CO observations of HD s cavity (Perez et al. submitted) 3) Inferring the mass from hydro simulations (work in progress)

4 HD basics H-band Subaru / Fukagawa et al Herbig Ae star / spectral type F6IIIe M? =2 2.5M Most likely in Lupus molecular cloud at 140 pc Age ~2 Myr Large stellar accretion rate. Ignacio Mendigutia s talk: Ṁ = M yr 1

5 HD s disk K-band NaCo/ Casassus et al Nearly face-on disk with a large dust-depleted cavity 1 =140 au GAP INNER DISK LARGE EXCESS DISK 0.1 Msun

6 0.3 flows of gas through the gap b CO 2 1 SIMON CASASSUS TALK CO(3-2) and HCO+ ALMA band 7 / Casassus et al Nature CO detection inside cavity non-keplerian gas inside the cavity (skewed) d accretion streamers flowing through the gap 1 HCO Angular position east (arcsec)

7 Spiral arms in the outer disk VALENTIN CHRISTIAENS TALK 1.5" 1" 0.5" 0" 0.5" 1" 1.5" 100 (d) S4 H1 S3 S2 near-ir polarimetry 1" Avenhaus et al " Distance (AU) 0 S5 S1 0" Distance (arcsec) 0.5" 100 S6 H2 see also Canovas et al " Distance (AU)

8 Outer disk horseshoe 0.3 FRANCOIS MÉNARD S TALK 2 a continuum at GHz 1 / 0 1 Casassus et al Nature b C position north (arcsec) c Continuum Asymmetry in dust continuum. Planet induced pressure maxima / vortex? or azimuthal grain size segregation / varying gas-todug ratio? what s going on with the gas? d

9 CO gas emission from inside the cavity (Perez et al. submitted) Band 6 ALMA data Beam 0.82 x beams inside cavity Aim: estimate gas conditions and mass inside the cavity *only gas. not continuum

10 3 isotopologues INTERVENING CLOUD AT 4.5 KM/S

11 13CO J=2-1 C ves of same line-of-sight velocity on the surface of a Keplerian disc formed mass, as viewed by an observer located towards the bottom of the page. The between the disc normal and the line-of-sight, is i =90. The shaded areas ith line-of-sight velocity in between 100 and 200 km s 1 (blue), 500 and e), and between 900 and 1100 km s 1 (yellow). The dot-dashed line repre r at a radius R =10R. Figure adapted from Horne & Marsh ( rves with constant radial v n Earth. Th

12 once identified the emission from inside the cavity isotopologues line ratios give us optical depth inside the disk cavity, 12CO is optically thick, while 13CO and C18O are mostly optically thin. 13CO and C18O trace better the underlying density distribution M gas / line intensity ) M gas M

13 Simple toy model axisymmetric tapered disk constant abundance (r)/ c gap depth outer disk Rout hydrostatic equilibrium dust cavity use LIME for radiative transfer R[AU] fit in visibility plane

14 high velocity gas is spatially sensitive to inclination and central mass Best fit yields: i 28 o M? 2.5M M gap = M R gap 90 au Gas cavity < dust cavity

15 Work in progress MJ OPEN 4MJ RIGID 16MJ OPEN 16MJ RIGID gap,wall (q,, h/r) Density/D e-05 wall MagAO / Close et al e-06 gap r [AU] Properties of the underlying planetary system (if present) may be inferred from the disk geometry. Constrain planet and disk parameters by comparing our data with hydro models.

16 Simulations gap,wall (q,, h/r) 1) resolve the disk well in 2D, and hopefully 3D 2) cover a large range of density gradients 3) the gap converges to a steady state 4) planet accretion 1e+0 Fung et al Σ gap / Σ 0 1e-1 1e-2 PEnGUIn ZEUS90 1e t / P p

17 Simulations gap,wall (q,, h/r) 1) resolve the disk well in 2D, and hopefully 3D 2) cover a large range of density gradients 3) the gap converges to a steady state 4) planet accretion two different temperature profiles Mulders et al. 2014

18 Large gap probably carved by a companion object. (photoevaporation ruled out by accretion and amount of gas) For the contrast we see in gas, the planet must be between 1 and 10 Jupiters. We now know there are about 2 Jupiter masses of gas available inside the cavity. (Perez et al. submitted) Now let s hear Simon, Valentin and Francois