AAS Meeting #193 - Austin, Texas, January 1999
Session 22. Various Aspects of Stellar Evolution
Oral, Wednesday, January 6, 1999, 10:00-11:30am, Room 9 (C)

## [22.06] The Angular Diameter of \delta2 Lyrae

J. J. Sudol, H. M. Dyck, J.A. Benson (U.S. Naval Obs.), N. M. White (Lowell Obs.), R. R. Thompson (Univ. of Wyoming)

We have measured the angular diameter of \delta2 Lyrae at 1.25 and 1.65 \mu{\rm m} at the Navy Prototype Optical Interferometer. Angular diameter measurements of \delta2 Lyrae have been reported from the Mark III Interferometer at 0.550, 0.712, 0.754, and 0.800 \mu{\rm m} and from the Infrared-Optical Telescope Array at 2.20 \mu{\rm m}. The variation in the measured angular diameter of \delta2 Lyrae with wavelength is larger than the uncertainties in the measurements. We discuss the interpretation of this diameter data in terms of atmospheric extension and limb darkening.