Mira Variables, Stellar Evolution and Galactic Structure

The Galactic Kinematics of Mira Variables

The galactic kinematics of Mira variables derived from radial velocities, Hipparcos proper motions and an infrared period-luminosity relation are reviewed. Local Miras in the 145-200day period range show a large asymmetric drift and a high net outward motion in the Galaxy. Interpretations of this phenomenon are considered and (following Feast and Whitelock 2000) it is suggested that they are ou...

“Real-Time” Evolution in Mira Variables

After a brief review of our current understanding of Miras and their evolutionary status, three aspects of “real-time” evolution in these and related stars are examined: • Chemical changes (O-rich to C-rich) due to third dredge-up • Period changes due to the effects of the helium-shell flash • The existence of “fossil” dust and gas shells. Studies of resolved gas and dust shells are highlighted...

Galactic Structure and Stellar Populations

The Milky Way Galaxy offers a unique opportunity for testing theories of galaxy formation and evolution. I discuss how large surveys, both photometric and spectroscopic, of Galactic stars are the keystones of investigations into such fundamental problems as the merging history – and future – of the Galaxy.

Stellar Structure and Evolution

Radial Structure of Galactic Stellar Disks

We present the results from our deep optical imaging survey µ V lim ≈ 26 − 27 mag/ 2 ′′ of a morphologically selected sample of 72 edge-on disk galaxies. The question of the global structure of galactic stellar disks, especially the radial surface brightness profile at large galactocen-tric distances, is addressed. We find that typical radial profiles are better described by a two-slope exponen...