Anomalous U(1) D-term contribution in type i string models

We study the D-term contribution for anomalous U(1) symmetries in type I string models and derive a general formula for the D-term contribution, assuming that the dominant source of supersymmetry breaking is given by the F terms of the dilaton, (overall) moduli, or twisted moduli fields. On the basis of the formula, we also point out that there are several features different from the case of heterotic string models. The differences originate from the different forms of the Kahler potential between twisted moduli fields in type I string models and the dilaton field in heterotic string models.