NOAO >   Observing Info >   Approved Programs >   2010A-0251

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Proposal Information for 2010A-0251


PI: Brian Donehew, Clemson University, briand@clemson.edu
Address: Physics Department, 118 Kinard Laboratory, Clemson, South Carolina 29634, USA

CoI: Sean Brittain, Clemson University

Title: Balmer Discontinuity Veiling as a measure of Mass Accretion Rates in Herbig Ae/Be stars

Abstract: Mass accretion rate is an important parameter in modeling the atmosphere and structure of the circumstellar disk surrounding a Herbig Ae/Be star. Accurate measurement of the mass accretion rate can also help determine if the magneto-accretion model for T Tauri stars, in which the magnetic field of the T Tauri star mediates accretion, is a viable model for Herbig Ae/Be stars. Unfortunately, the standard methods for measuring mass accretion in T Tauri stars are generally not useable for Herbig Ae/Be stars. However, Garrison (1978) observed that the Balmer Discontinuity for Herbig Ae/Be stars is weaker than for normal Main Sequence stars of the same spectral type, and suggested that this is due to veiling from the mass accretion luminosity. Muzerolle (2004) calculated the theoretical veiling due to mass accretion luminosity for a typical Herbig Ae/Be star undergoing magneto-accretion. Using Muzerolle's work as a model, it is possible to determine the mass accretion rates of Herbig Ae/Be stars by measuring the strength of the Balmer Discontinuity. Also, Br-gamma luminosity correlates with mass accretion luminosity in T Tauri stars, and we wish to test the applicability of this correlation to Herbig Ae/Be stars.


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NOAO >   Observing Info >   Approved Programs >   2010A-0251

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