DEPARTURES FROM THERMODYNAMIC EQUILIBRIUM IN CHROMOSPHERIC Mg I, Ca I, AND O I

Journal Article · Thu Mar 01 04:00:00 EST 1962 · Astrophysical Journal (U.S.)

DOI:https://doi.org/10.1086/147286· OSTI ID:4786819

Athay, R G; House, L L

Comparisons of intensities of Mg I and O I emission lines in the flash- spectrum of the low chromosphere reveal evidence of marked departures from a Boltzmann distribution of populations of energy levels. These departures are in the same sense as those found earlier for He I, viz., an overpopulation of the levels connected to the ground state through optically forbidden transitions relative to the levels with permitted transitions. A search for a similar effect in the populations of the excited singlets and triplets of Ca I did not indicate a significant departure from a Boltzmann distribution for the levels studied. Evidence is found that the ratio Ca I/Ca II is much greater than would be expected in thermodynnmic equilibrium. For Mg I, the optical thickness of the chromosphere in the triplet lines is obtained directly from the observed intensity of the forbidden ibtercombination line lambda 4571 (3/sup 3/P-3/sup 1/ S). Computed populations of energy levels for a model Mg I atom under a range of temperature and density show agreement with observational data for choices of chromospheric temperatures and densities consistent with a model departing from spherical symmetry. (auth)

• Research Organization: High Altitude Observatory, Boulder, Colo.
• NSA Number: NSA-16-016898
• OSTI ID: 4786819
• Journal Information: Astrophysical Journal (U.S.), Journal Name: Astrophysical Journal (U.S.) Vol. Vol: 135; ISSN ASJOA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ASTROPHYSICS
CALCIUM
CHROMOSPHERE
DENSITY
EMISSION
ENERGY LEVELS
HELIUM
IONS
MAGNESIUM
MAXWELL DISTRIBUTION
MEASURED VALUES
NUMERICALS
OXYGEN
PHYSICS
SPECTRA
SUN
TEMPERATURE
THERMODYNAMICS
THICKNESS