Email: catyp@astro.indiana.edu

Professor Catherine A. Pilachowski investigates the evolution of stars and the chemical history of the Milky Way Galaxy from studies of chemical composition of stars and star clusters. As stars evolve, chemical elements are synthesized by nuclear processes in the stars' interiors. These newly created elements appear in the stars' outer layers, where we can observe them. Changes in the surface composition of stars help us to understand what's going on inside the star, and to understand the process of stellar evolution.

Professor Pilachowski also uses her data on the compositions of stars to explore the chemical history of the Milky Way Galaxy. Since its formation 14 billion years ago, the Galaxy has been gradually enriched in the abundance of chemical elements as these elements have been produced in stars. Studies of the abundances of the chemical elements in the oldest stars can reveal the nature of the first generation of stars formed in the Galaxy, and the compositions of old stars can also tell us about the history of the Galaxy.

Instrumentation - Two fiber-fed, high dispersion echelle spectrographs are under construction in the Indiana University Department of Astronomy for use on the WIYN 3.5-m telescope and on IU's Spectrabot telescope, a 1.25-m robotic telescope located in the Morgan-Monroe State forest north of Bloomington. The spectrographs are designed to carry out a complete spectroscopic survey of stars with good proper motion and/or parallax measurements from the Hipparcos survey. For more information about the FHiRE and FHiREBot spectrographs, and for information about planned community access to these spectrographs, please see the FHiRE website.

Current students: Dennis Lamenti, Michael Grounds (IUPUI Engineering)

Globular Cluster Abundances - Studies of abundance variations among stars in globular clusters tell us about physical process involved in the formation of the cluster and during stellar evolution. The evolution of stars can be examined in detail through changes in the abundance of elements at the stellar surface from nucleosynthesis and mixing inside a star. These changes tell us about the physical conditions inside the star and about processes that create and bring new elements to the surface.

Projects underway are selected from a large survey of globular cluster giants obtained the Hydra multi-fiber spectrographs at the 3.5-m WIYN telescope and at the Cerro Tololo Interamerican Observatory. Spectra of nearly a thousand giants selected from more than a dozen clusters are available for analysis.

Current Students: Christian Johnson, Tara Angle, Sharina Haynes (Tennessee State, Fisk University)

Studies of Young Clusters - Two programs are underway with the goal of learning about the early evolution of planetary systems. The Open Cluster Planet Search (OCtPS), in collaboration with Sam Barden at the AAO and others, aims to investigate the fraction of stars with massive planets in star clusters of different ages, using multi-fiber spectroscopy. The second project, involving both multi-object spectroscopy and infrared photometry with the Spitzer Space Telescope, is a study of the debris disks and infalling bodies around A stars in young clusters.

Current students: TalaWanda Monroe, Randy Hamper

The Galactic Disk - Graduate student Heather Jacobson studies the chemical evolution of the outer disk of the Milky Way Galaxy. She is working in collaboration with Dr. Eileen Friel of the National Science Foundation.