H II region age indicators

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1986
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http://hdl.handle.net/10183/98358
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Abstract
The evolution of some properties of H II regions such as the relative volume R of the He⁺ and H⁺ zones, the equivalent width Wнβ of the Hβ emission line and the ratio [O III]/Hβ of the lines [O II] λλ4959, 5007 to Hβ, was studied through models which take into account: a single burst for the formation of the ionizing association with different initial mass function IMF (1 ≤ x ≤ 3) and upper stellar mass limits (30 ≤ Mu/Mѳ ≤ 120); different chemical composition models of stellar evolution with a  ... 
The evolution of some properties of H II regions such as the relative volume R of the He⁺ and H⁺ zones, the equivalent width Wнβ of the Hβ emission line and the ratio [O III]/Hβ of the lines [O II] λλ4959, 5007 to Hβ, was studied through models which take into account: a single burst for the formation of the ionizing association with different initial mass function IMF (1 ≤ x ≤ 3) and upper stellar mass limits (30 ≤ Mu/Mѳ ≤ 120); different chemical composition models of stellar evolution with and without mass loss. It was found that Wнβ, R and [OIII]/Hβ decrease monotonically as a function of time and consequently they are good H II region age indicators.  ... 
In
Astronomy and astrophysics. Berlin. Vol. 156, no. 1/2 (Feb. 1986), p. 111-120
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Foreign
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