The plot shown above is an example of the approach developed by Ed Fitzpatrick and myself for codifying the properties of UV extinction curves by a few simple, physically meaningful functions.

Research activities:

I have made a number of contributions to the study of the properties of interstellar dust. Much of this work was carried out in collaborations with Blair Savage and Ed Fitzpatrick.

Helped to create a standard approach to the analysis of interstellar extinction. Even the more recent empirical model described by Cardelli et al. (the CCM family of extinction curves) contains the Fitzpatrick and Massa formalism at its core.

Provided the first rigorous demonstration that the form of UV extinction is highly variable, even in the diffuse interstellar medium.

Provided one of the first demonstrations that the form of UV extinction is sensitive to its environment.

Established the formulation for the impact of systematic errors on extinction curves which has been adopted as the standard in the field.

Quantified the effects of extinction uncertainties on a stellar continuum dereddened with an arbitrary extinction curve.
While I am not currently active in this field, I do remain abreast of the literature.

Some relevant publications:

Invited Review: ``Measurements of Interstellar Extinction'', D. Massa and B.D. Savage 1989, in IAU Symp. No 135, ``Interstellar Dust'', eds. L.J. Allamandola and A.G.G.M. Tielens, p. 3

Papers in Refereed Journals:

``An Analysis of the Shapes of UV Extinction Curves III. An Atlas of UV Extinction Curves'', E.L. Fitzpatrick & D. Massa 1990, ApJS, 72, 163

``An Analysis of the Shapes of UV Extinction Curves II. The Far-UV Extinction'', E.L. Fitzpatrick & D. Massa 1988, ApJ, 328, 734

``The Variability of UV Extinction-Curve Shapes and Its Impact Upon Dereddened UV Energy Distributions'', D. Massa 1987, AJ, 94, 1675

``An Analysis of the Shapes of UV Extinction Curves I. The 2175 Å Bump'', E.L. Fitzpatrick & D. Massa 1986, ApJ, 307, 286

``The UV Extinction Toward 5 Open Clusters and the Accuracy of IUE Extinction Measurements'', D. Massa & E.L. Fitzpatrick 1986, ApJS, 60, 305

``A Catalog of Ultraviolet Interstellar Extinction Excesses for 1415 Stars'', B.D. Savage, D. Massa, M. Meade, & P.R. Wesselius 1985, ApJS, 59, 397

``UV Observations of Interstellar Extinction Near the Cep OB3 Molecular Cloud'', D. Massa & B.D. Savage 1984, ApJ, 279, 310

``Peculiar UV Interstellar Extinction'', D. Massa, B.D. Savage, & E.L. Fitzpatrick 1983, ApJ, 266, 662

``IUE Observations of Eight OB Stars in NGC 2244: UV Continua and Extinction'', D. Massa & P.S. Conti 1981, ApJ, 248, 201

``Vector Space Methods of Photometric Analysis. III. The Two Components of Ultraviolet Extinction'', D. Massa 1980, AJ, 85, 1651

``Vector Space Methods of Photometric Analysis: Applications to O Stars and Interstellar Reddening'', D. Massa & C.F. Lillie 1978, ApJ, 221 833

Derck Massa,
Raytheon ITSS