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Session 71 - Space Astronomy in the Next Millennium.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

[71.11] Precise Photometry Mission -- Measuring Stellar Microvariability from Space

T. M. Brown (HAO), W. Borucki (NASA/Ames), S. Frandsen (U. Aarhus), R. L. Gilliland (STScI), A. Jones (UIUC), R. W. Noyes (CfA), T. Tarbell, A. Title (Stanford-Lockheed Inst.), R. K. Ulrich (UCLA)

Atmospheric scintillation limits the precision attainable by ground-based photometry; this limitation is a major obstacle to progress in several fields, notably asteroseismology of Sun-like stars. A space-borne photometric telescope could operate near the shot noise limit, removing this obstacle and providing new opportunities for inquiry. As part of the program for New Mission Concepts in Astrophysics, we are studying the scientific rewards and technological challenges associated with a Precise Photometry Mission (PPM). The baseline performance goal for the PPM is to measure solar-like pulsations (amplitude 3 \mumag) in G stars in the Hyades with a S/N ratio of 4 in 10 days of observing time. This performance would also allow detection of transits of Earth-sized planets of main-sequence stars, extremely precise characterization of the light curves of micro-lensing events, and other novel applications.

The technical approach envisioned for the PPM is wide-band CCD photometry. The study that is underway focuses on two aspects of the required technology: Are CCD detectors able to provide the necessary very high S/N within the spacecraft operating environment? (2) Can new lightweight mirror and telescope structure technology be applied to yield significant reductions in mission cost? We are addressing both questions with laboratory tests, including time-series performance tests of suitable CCDs, and thermal and mechanical tests of a SiC telescope mirror. In addition to describing PPM's scientific aims and technical rationale, we report preliminary results of the CCD tests.

Program listing for Wednesday