THE PROPAGATION OF Ly{alpha} IN EVOLVING PROTOPLANETARY DISKS
We study the role resonant scattering plays in the transport of Ly{alpha} photons in accreting protoplanetary disk systems subject to varying degrees of dust settling. While the intrinsic stellar far-UV (FUV) spectrum of accreting T Tauri systems may already be dominated by a strong, broad Ly{alpha} line ({approx}80% of the FUV luminosity), we find that resonant scattering further enhances the Ly{alpha} density in the deep molecular layers of the disk. Ly{alpha} is scattered downward efficiently by the photodissociated atomic hydrogen layer that exists above the molecular disk. In contrast, FUV-continuum photons pass unimpeded through the photodissociation layer and (forward-)scatter inefficiently off dust grains. Using detailed, adaptive grid Monte Carlo radiative transfer simulations we show that the resulting Ly{alpha}/FUV-continuum photon density ratio is strongly stratified; FUV-continuum-dominated in the photodissociation layer and Ly{alpha}-dominated field in the molecular disk. The enhancement is greatest in the interior of the disk (r {approx} 1 AU) but is also observed in the outer disk (r {approx} 100 AU). The majority of the total disk mass is shown to be increasingly Ly{alpha} dominated as dust settles toward the midplane.
- OSTI ID:
- 21587477
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 739; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BINARY STARS
BOSONS
CALCULATION METHODS
DENSITY
DISSOCIATION
DUSTS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY TRANSFER
ERUPTIVE VARIABLE STARS
FAR ULTRAVIOLET RADIATION
HEAT TRANSFER
INELASTIC SCATTERING
LYMAN LINES
MASSLESS PARTICLES
MONTE CARLO METHOD
PHOTONS
PHYSICAL PROPERTIES
PROTOPLANETS
RADIANT HEAT TRANSFER
RADIATIONS
RESONANCE SCATTERING
SCATTERING
SIMULATION
STARS
T TAURI STARS
ULTRAVIOLET RADIATION
VARIABLE STARS