7.1 Introduction

This chapter presents infrared JHK photometry of the representative sample and a new technique for separating out the interstellar reddening and circumstellar excess. We then go on to correlate the derived circumstellar excess of the objects in the sample, with their emission line strengths, spectral types and rotational velocities. Throughout this chapter we shall be using non-parametric correlation analysis, specifically the Spearman rank correlation coefficient; (see Press et al., 1992) to study these relationships. In this way we impose no assumptions about the form of the dependence between parameters.

In section 7.2 we describe our observations and how we carried out the preliminary data reduction. Section 7.3 describes the process we have used to separate the circumstellar excess and interstellar reddening associated with observations of Be stars. In section 7.4 we present the correlations we have found between the separated excesses, reddenings and other observed quantities. Finally Section 7.5 presents our conclusions.