INSTRUMENT PERFORMANCE IN KEPLER's FIRST MONTHS
- SETI Institute/NASA Ames Research Center, MS 244-30, Moffett Field, CA 94035 (United States)
- NASA Marshall Space Flight Center, VP60, Huntsville, AL 35812 (United States)
- Ball Aerospace and Technologies Corp., 1600 Commerce Street, Boulder, CO 80301 (United States)
- Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
- Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
The Kepler Mission relies on precise differential photometry to detect the 80 parts per million (ppm) signal from an Earth-Sun equivalent transit. Such precision requires superb instrument stability on timescales up to {approx}2 days and systematic error removal to better than 20 ppm. To this end, the spacecraft and photometer underwent 67 days of commissioning, which included several data sets taken to characterize the photometer performance. Because Kepler has no shutter, we took a series of dark images prior to the dust cover ejection, from which we measured the bias levels, dark current, and read noise. These basic detector properties are essentially unchanged from ground-based tests, indicating that the photometer is working as expected. Several image artifacts have proven more complex than when observed during ground testing, as a result of their interactions with starlight and the greater thermal stability in flight, which causes the temperature-dependent artifact variations to be on the timescales of transits. Because of Kepler's unprecedented sensitivity and stability, we have also seen several unexpected systematics that affect photometric precision. We are using the first 43 days of science data to characterize these effects and to develop detection and mitigation methods that will be implemented in the calibration pipeline. Based on early testing, we expect to attain Kepler's planned photometric precision over 80%-90% of the field of view.
- OSTI ID:
- 21308722
- Journal Information:
- Astrophysical Journal Letters, Vol. 713, Issue 2; Other Information: DOI: 10.1088/2041-8205/713/2/L92; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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