Introduction to MIRSI Science

MIRSI is a mid-infrared camera system with both spectroscopic and imaging capabilities which will penetrate the dusty environments around very young and very old stars in order to study the process of stellar evolution. Circumstellar envelopes are found around stars at different evolutionary phases, and material is continuously exchanged between these envelopes and their ambient mediums through mass accretion and mass outflow. The properties of the gas and dust of which this material is comprised are altered as the material is cycled. Since new stars will ultimately form from the material ejected by evolved stars, the processing of gas and dust through stellar evolution has important consequences for the stellar populations of galaxies. Our understanding of stellar evolution is limited in part by our incomplete knowledge of the physical conditions in circumstellar envelopes and the relation of the envelopes to their ambient mediums. In order to study these environments, we must observe at the infrared wavelengths at which these dusty regions emit most of their luminosity. In addition, since dust absorbs most direct stellar radiation at shorter wavelengths and re-emits it at longer infrared wavelengths, the embedded luminosity sources which power these regions can only be studied indirectly at longer wavelengths. There are a host of diagnostic spectral features of both dust and gas which appear in the infrared.

MIRAC (Hoffmann et al. 1993, Proc. SPIE, 1946, 449) 12-image mosaic at 20.6 microns of the Orion Nebula, taken at IRTF. The white box represents MIRSI's large field of view. MIRSI will be suited to study galactic star-forming regions such as these using both imaging and spectroscopy in the 10 and 20 micron atmospheric windows.

Equipped with wide-field imaging and low resolution spectroscopic modes, MIRSI is uniquely suited to study:

Related Links

MIRSI homepage
MIRSI instrument description and specifications
Infrared Astronomy Lab at the BU IAR
MIRAC: A Mid-Infrared Array Camera
BU Institute for Astrophysical Research