Collaborative Research: The 3-Helium Problem

Trustees Of Boston University, Boston

Investigators

Abstract

Bania, Thomas " Collaborative Research: The 3- Helium Problem " AST- 0098047 Determination of the isotopic abundances of the light elements is fundamental in probing the earliest nucleosynthesis in our universe. During the first 1000 seconds, significant amounts of light elements 2-H, 3-He, 4-He and 7-Li were produced. This investigation focuses on the 3-He isotope. A primordial abundance is an ultimate aim but the contribution by the generation of this isotope by nuclear burning within common solar-type stars must first be evaluated. We would expect the contamination from this component to increase with time and also to be larger in areas which have had the highest rates of star formation in the past. These correlations are not seen and a prime goal of the present proposal is to understand why they are absent. The plan is to continue a survey of planetary nebulae and H II regions to determine 3-He abundances in different parts of the galaxy. Earlier work had revealed that small but significant excesses of 3-He were present in the planetary nebula NGC 3242 showing that enrichment had taken place. With improved facilities at Arecibo and Green Bank, it is expected that many more objects can be observed now.