Stellar winds are the continuous outflow of material from stars. The ejection of material plays a major role in the life cycle of stars. In the case of massive stars, the winds remove more than half of the star's original mass before the star explodes as a supernova. In this book we will explore the many mechanisms that can lead a star to eject matter in the form of a steady stellar wind. We will also discuss the interaction of winds with the interstellar medium of our galaxy, and the effects of mass loss on the evolution of a star. We start by giving in this chapter a brief overview of the historical development of the subject, especially focusing on the early observations and theoretical advances that led us to our current level of understanding.

Historical introduction

The early developments

The names ‘solar wind’ and ‘stellar winds’ were both coined by Eugene Parker (1958, 1960). However, the origins of the basic ideas regarding mass loss from stars arose long before that.

The earliest phase in the development of the subject concerns the realization that a few stars are like ‘novae’, in having spectra with very broad emission lines. Novae are sudden outbursts of light from certain types of stars, and the outbursts are also associated with the high speed ejection of material. Tycho Brahe's observation of a ‘new star’ or nova in 1572 marks the birth of stellar astronomy as a study of objects that are not perfect celestial objects, but rather ones that can change in interesting ways.