The Structure of the DoAr 25 Circumstellar Disk

Sean M. Andrews; A. M. Hughes; D. J. Wilner; Chunhua Qi

doi:10.1086/588730

paper

The Structure of the DoAr 25 Circumstellar Disk

arXiv:0804.0437 · doi:10.1086/588730

Abstract

We present high spatial resolution (< 0.3" = 40 $A U) S u bmi l l im e t er A r r a y o b ser v a t i o n so f t h e 865 mi cr o n co n t in uu m e mi ss i o n f r o m t h ec i r c u m s t e l l a r d i s k a r o u n d t h ey o u n g s t a r D o A r 25. D es p i t e i t s b r i g h t mi l l im e t er e mi ss i o n, t hi sso u r cee x hibi t so n l y a co m p a r a t i v e l y s ma l l in f r a r e d e x cess an d l o w a ccr e t i o n r a t e, s ug g es t in g t ha tt h e ma t er ia l an d s t r u c t u r a l p r o p er t i eso f t h e inn er d i s k ma y b e inana d v an ce d s t a t eo f e v o l u t i o n . A s im pl e m o d e l o f t h e p h y s i c a l co n d i t i o n s in t h e d i s k i s d er i v e df r o m t h es u bmi l l im e t er v i s ibi l i t i es an d t h eco m pl e t es p ec t r a l e n er g y d i s t r ib u t i o n u s in g a M o n t e C a r l or a d ia t i v e t r an s f er co d e . F or t h es t an d a r d a ss u m pt i o n o f ah o m o g e n eo u s g r ain s i z e d i s t r ib u t i o na t a l l d i s k r a d ii, t h er es u l t s in d i c a t e a s ha l l o w s u r f a ce d e n s i t y p r o f i l e,$ Σ\propto r^{-p}$ with p = 0.34, significantly less steep than a steady-state accretion disk (p = 1) or the often adopted minimum mass solar nebula (p = 1.5). Even though the total mass of material is large (M_d = 0.10 M_sun), the densities inferred in the inner disk for such a model may be too low to facilitate any mode of planet formation. However, alternative models with steeper density gradients (p = 1) can explain the observations equally well if substantial grain growth in the planet formation region (r < 40 AU) has occurred. We discuss these data in the context of such models with dust properties that vary with radius and highlight their implications for understanding disk evolution and the early stages of planet formation.

ApJL in press

References in corpus (6)

Cited by in corpus (1)

Protoplanetary Disk Structures in Ophiuchus