Although Serkowski used a single value K=1.15 in representing all the observed interstellar linear polarization curves by his empirical relation p ( λ ) / P m a x =exp (-K 1 n 2 ( λ m a x / λ ) ), where p m a x is the maximum polarization at wavelength λ m a x , we have noticed a meaningful variation in K from observations of 72 stars. By comparing K's with P m a x / E B − V a n d w i t h λ m a x , we have examined how the shape of the polarization curve is related with the degree of grain alignment on one hand, and with grain sizes on the other. We have shown that correlations between K, P m a x / E B − V a n d w i t h λ m a x , are consistent with the idea of Davis-Greenstein mechanism for grain alignment.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. UNIFORMITY OF NORMALIZED LINEAR POLARIZATION CURVE
Ⅲ. SHAPE OF POLARIZATION CURVE AND DEGREE OF ALIGNMENT
Ⅳ. CONCLUSION
ACKNOWLEDGEMENTS
REFERENCES

• SEUNG SOO HONG(Department of Astronomy, College of Natural Sciences, Seoul National University)
• HYUNG MOK LEE(Department of Astronomy, College of Natural Sciences, Seoul National University)