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The Time-Dependent Chemistry of Cometary Debris in the Solar CoronaRecent improvements in solar observations have greatly progressed the study of sungrazing comets. They can now be imaged along the entirety of their perihelion passage through the solar atmosphere, revealing details of their composition and structure not measurable through previous observations in the less volatile region of the orbit further from the solar surface. Such comets are also unique probes of the solar atmosphere. The debris deposited by sungrazers is rapidly ionized and subsequently influenced by the ambient magnetic field. Measuring the spectral signature of the deposited material highlights the topology of the magnetic field and can reveal plasma parameters such as the electron temperature and density. Recovering these variables from the observable data requires a model of the interaction of the cometary species with the atmosphere through which they pass. The present paper offers such a model by considering the time-dependent chemistry of sublimated cometary species as they interact with the solar radiation field and coronal plasma. We expand on a previous simplified model by considering the fully time-dependent solutions of the emitting species' densities. To compare with observations, we consider a spherically symmetric expansion of the sublimated material into the corona and convert the time-dependent ion densities to radial profiles. Using emissivities from the CHIANTI database and plasma parameters derived from a magnetohydrodynamic simulation leads to a spatially dependent emission spectrum that can be directly compared with observations. We find our simulated spectra to be consistent with observation.
Document ID
20160005848
Document Type
Reprint (Version printed in journal)
Authors
Pesnell, W. D. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Bryans, P. (Adnet Systems, Inc. Greenbelt, MD, United States)
Date Acquired
May 5, 2016
Publication Date
March 24, 2015
Publication Information
Publication: The Astrophysical Journal
Volume: 785
Issue: 1
Subject Category
Solar Physics
Report/Patent Number
GSFC-E-DAA-TN31870
Funding Number(s)
CONTRACT_GRANT: NNG12PL17C
Distribution Limits
Public
Copyright
Other
Keywords
sun: corona
Sun
comets