Infalling Planetesimals in Young Star Clusters

Indiana University, Bloomington IN

Investigators

Abstract

PI: Pilachowski Dr. Pilachowski is awarded funds at Indiana University to use the recently discovered "falling evaporative bodies" (FEBs) in young star systems to study the timescale for the formation of planets. FEBs are planetesimals whose orbits are perturbed by newly formed planets. The planetesimals are either ejected from the planetary system or sent inward on orbits that impact or graze the central star. Near the star, the planetesimals are heated and turned to gas, and can be detected by their transient spectral absorption features. The FEBs offer direct evidence of planets and planetesimals in the star system, and also provide information about the dynamics of the system and the composition of the planetesimals. Observations of FEBs in a sample of young stars with well-defined masses and ages may constrain the timescale of planet formation and/or the mechanism of orbital migration. Dr. Pilachowski will examine late B and early A dwarf stars in young star clusters ranging in age from a few million years up to 30 million years to explore the timescales over which planetesimals may be cleared out of young solar systems by the formation of planets and by orbital migration. The stars will be monitored spectroscopically using the 3.5-m Wisconsin-Indiana-Yale-NOAO (WIYN) telescope and multi-object spectrograph. The PI will involve both graduate and undergraduate students in the work, and expects that this study of "comets" in extra-solar planetary systems is likely to attract broad public interest and to fire the imaginations of children. ***