imaging the candidate proto-planet HL Tau b

Jane Greaves

University of St Andrews

Anita Richards, Tom Muxlow (Jodrell Bank Centre for Astrophysics)

Ken Rice, Duncan Forgan, Bruce Sibthorpe (Edinburgh)

growth phase

• when does dust grow into (unobservable) planetesimals?

Greaves & Rice 2011

HL Tau

• Class I low-mass protostar with massive envelope

Kwon, Looney & Mundy 2011CARMA, 1.3mm, 0.15"

Welch et al. 2004BIMA, 1.4mm, 0.3"

HL Tau b

• high-resolution imaging of large dust in the radio

Greaves, Richards, Rice & Muxlow 2008VLA, 1.3cm, 0.08-0.11"

...revisited

• re-observed recently with EVLA (preliminary reduction)

courtesy Disks@EVLA, PI Claire Chandler

disc instability

• SPH simulation naturally forms 8MJup object at 75 AU (vs. ~10-14MJup at 65 AU observed)

instability trigger?

• XZ Tau flyby of HL Tau at ~600 AU, ~1600 years ago?

Anglada et al. 2007Ducourant et al. 2005

disc interaction

• SPH simulation of such an encounter

Forgan & Rice

disc perturbation

• recent image with SCUBA-2 at 450 m

Greaves, Gibb, Sibthorpe et al.450 m, 8"

future observations

• have test-time for Key Project PEBBLES with eMERLIN at 5cm – survey of dust discs at longest wavelength so far!