Resolving the gap and AU-‐scale asymmetries in pre ... · Ori is filled with substan al amounts...

Resolving  the  gap  and  AU-­‐scale  asymmetries  in    pre-­‐transi�onal  disks  with  mul�-­‐wavelength  interferometry  

Stefan  Kraus1,2,3,  Michael  Ireland4,  Michael  Sitko5,6,10,  John  Monnier3,  Nuria  Calvet3,  Catherine  Espaillat2,  Carol  Grady7,    Tim  Harries1,  Sebas�an  Hönig8,  Ray  Russell9,10,  Daryl  Kim9,10,  Jeremy  Swearingen5,  Chelsea  Werren5,  David  Wilner2  

 (1)  University  of  Exeter,  (2)  Harvard-­‐Smithsonian  Center  for  Astrophysics,  (3)  University  of  Michigan,  (4)  Macquarie  University,    

(5)  University  of  Cincinna�,  (6)  Space  Science  Ins�tute,  (7)  Eureka  Scien�fic  Inc.  and  Goddard  Space  Flight  Center,    (8)  University  of  California  Santa  Barbara,  (9)  The  Aerospace  Corpora�on,  (10)  Visi�ng  Scien�st  NASA  IRTF  

H  band  

K  band  

L  band  

Op�cally  thick  inner  disk  (R=0.18-­‐0.27  AU),  

resolved  by    VLTI/AMBER  +  KI/ASTRA    

near-­‐infrared  interferometry  

Op�cally  thin  material    located  in  the  gap  (R=0.27-­‐46  AU),  

resolved  by  VLTI/MIDI  +  Gemini/TReCS    mid-­‐infrared  speckle  interferometry  

Pre-­‐transi�onal   disks   exhibit   a   significantly  reduced   mid-­‐infrared   excess   compared   to  classical   (T   Tauri-­‐type)   protoplanetary   disks,  possibly  indica�ng  a  gapped  disk  structure.    We   emp l o y   n e a r -­‐   a n d   m i d -­‐ i n f r a r e d  interferometry  in  order  to  study  the  structure  of  these  objects  and  to  solve  ambigui�es  that  result  from  fi�ng  the  SED  alone.  

Density  inhomogenei�es    in  the  gap  region,  

detected  with  Keck/NIRC2    aperture  masking  interferometry  

Spa�al  Frequency  [106  λ]  

Visib

ility  

Spa�al  Frequency  [106  λ]   Spa�al  Frequency  [106  λ]  

è The   detected   asymmetries  trace   complex   density   structures  on  AU-­‐scales.    

è We   cau�on   that   these  signatures   can   be   easily  misinter-­‐preted  as  companion  signatures.  

è The  gap   in  V1247  Ori   is  filled  with  substan�al  amounts  of  op�cally  thin  material  (Σgap≈ 9×10-­‐6  g/cm2)  with  a  carbon-­‐dominated   dust  mineralogy.     The   presence   of   this   op�cally  thin  material  cannot  be  deduced  from  the  SED  alone.  

è Our  IRTF/SpeX+BASS  spectra  show  strong  hydrocarbon-­‐related   (“PAH”)   line-­‐emission,   whose   spa�al   origin   we  constrain  with  MIDI  interferometry  to  within  the  gap  region.  

è We   detect   a   narrow  ring   of   op�cally   thick   hot  dust  at  the  dust  sublima�on  radius,   followed   by   an  extended  disk  gap.  

V1247  Ori,  Ar�st  Im

pressio

n,  NASA/JPL-­‐Calte

ch  

Reference:  Kraus  et  al.  2013,  ApJ  768,  80;      Contact:  skraus@astro.ex.ac.uk  This  work  is  supported  at  The  Aerospace  Corpora�on  by  the  Independent  Research  and  Development  program.  

RESULTS:  V1247  Ori    Spa�ally   resolved   observa�ons  provide   unambiguous   evidence   for  a  gapped  disk  structure.  

  The   gap   is   filled   with   substan�al  amoun t s   o f   o p� c a l l y   t h i n  carbonaceous   dust,   possibly  indica�ng  a  par�cularly  early  stage  of  disk  clearing.    

  Complex   density   inhomogenei�es  might   reflect   the   dynamical  interac�on   of   disk   material   with  the  gap-­‐opening  bodies.  

Future  direc�ons  of  work:  

  Observa�ons  on  a  larger  sample  of  transi�onal   &   pre-­‐transi�onal  disks   are   needed   to   establish   the  evolu�onary   sequence   of   disk  clearing.  

  Mul�-­‐epoch   interferometric  imaging   could   unravel   the   origin,  structure   and   �me-­‐evolu�on   of  the  detected  asymmetries.