45. Stellar Classification

Extract

As an introduction to this report I would like to cite two comments from the book MK Process and Stellar Classification (ed. by R.F. Garrison, 1984). The first is from the article by W.W. Morgan The MK system and the MK process: “The MK system furnishes a satisfactory frame of reference for stars of Population I in the solar neighborhood; but when we consider the variety of stellar spectra encountered in our galaxy and in other stellar systems we are unable to classify many stars satisfactorily from the MK standards alone. What we now require is a more general frame of reference – or frames of reference – that will accept with precision a greater variety of ‘specimens’ (stellar spectra).” The second is an excerpt from one of the conclusions in the article by D.L. Crawford The relationship between the MK system and photometric classification: “The future potential of all this classification work is great. Technological change is rampant, and most interesting. New and powerful 1(λ) machines will be with us soon, as well as direct CCD photometers. Their power is great and we’ll all end up using them. The opening of new wavelength regions is a fantastic advantage to classifiers. The challenges and opportunities are vast.”

During the last three years there have been technical improvements in CCD detectors and as a result they are now much better adapted to the needs of photometry and spectroscopy. Signal processing by modern computers now permits rapid utilization of large quantities of information. Technical progress in detectors and computer science now provides us with powerful and relatively low-cost tools for computation, and leads us to view with optimism the development of the powerful 1(A) machines anticipated by Crawford.