[IGPP Everyone] Space Physics Seminar, Fri. 11/18 3:30pm: "Signatures of Young Planets in the Continuum Emission From Protostellar Disks" (Neal Turner (JPL/Caltech) and Andrea Isella (Rice Univ.))

[Emmanuel V. Masongsong]

SPACE PHYSICS SEMINAR 


DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES 

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES 

UNIVERSITY OF CALIFORNIA, LOS ANGELES 



Signatures of Young Planets in the Continuum Emission From Protostellar Disks 



Neal Turner (JPL/Caltech) and Andrea Isella (Rice Univ.) 


Many protostellar disks show central cavities, rings or spiral arms likely caused by low-mass stellar or planetary companions, yet few 
such features are conclusively tied to bodies embedded in the disks. We note that even small features on the disk's surface cast shadows, 
because the starlight grazes the surface. We therefore focus on accurately computing the disk's thickness, which depends on its 
temperature. We present models with temperatures set by the balance between starlight heating and radiative cooling, that are also in 
vertical hydrostatic equilibrium. The planet has 20, 100, or 1000 Earth masses, ranging from barely enough to perturb the disk 
significantly, to clearing a deep tidal gap. The hydrostatic balance strikingly alters the model disk's appearance. The planet-carved 
gap's outer wall puffs up under starlight heating, throwing a shadow across the disk beyond. The shadow appears in scattered light as a 
dark ring that could be mistaken for a gap opened by another more distant planet. The surface brightness contrast between outer wall 
and shadow for the 100-Earth-mass planet is almost an order of magnitude greater than a model neglecting the temperature 
disturbances. The shadow is so deep it largely hides the planet-launched spiral wave's outer arm. Temperature gradients are 
such that outer low-mass planets undergoing orbital migration will converge within the shadow. Furthermore the temperature perturbations 
affect the shape, size and contrast of features at millimeter and centimeter wavelengths. Thus radiative heating and cooling are key to 
the appearance of protostellar disks with embedded planets. 




Friday, November 18 , 2016 

Room 6704 Geology 

3:30 - 5:00 PM 



In Charge 

Marco Velli 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.igpp.ucla.edu/pipermail/everyone/attachments/20161115/d4c3a729/attachment.html>