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Article Contents
- ABSTRACT
- 1.INTRODUCTION
- 2.DETERMINATION OF PHYSICAL PARAMETERS
- 2.1.Measurements of Relative Emission Line Strengths and
Errors
- 2.2.Determination of Reddening and Underlying H I
Absorption from Balmer Lines
- 2.3.Electron Temperature Determinations from
Collisionally Excited Lines
- 2.4.Electron Density Determinations from Collisionally
Excited Lines
- 3.CONVERTING INDIVIDUAL HE I LINES INTO HE/H ABUNDANCES
- 3.1.He I and H I Emissivities
- 3.2.Collisional Enhancement of He I Emission Lines
- 3.3.The Effects of Underlying Stellar Absorption
- 3.4.He I Optical Depth Effects
- 3.5.Ionization Correction Factors
- 4.SELF-CONSISTENT METHODS FOR
EXTRACTING THE 4 He ABUNDANCE
- 4.1.Using 3 Lines
- 4.2.Using 5 Lines
- 4.3.Using 6 Lines
- 5.TEST CASES AND EXAMPLES
- 5.1.Cases with no Systematic
Errors
- 5.2.Cases with Systematic Errors in
I(
3889)
- 5.3.Cases with Systematic Errors in
I(
7065)
- 6.DISCUSSION
- A.MONTE CARLO ESTIMATES OF REDDENING AND UNDERLYING
BALMER ABSORPTION
- B.MONTE CARLO ESTIMATES OF REDDENING AND UNDERLYING BALMER
ABSORPTION IN REAL OBSERVATIONS
- C.MONTE CARLO ESTIMATES OF SELF-CONSISTENT HELIUM LINE
RATIOS
- REFERENCES