<title>CCD photometry tests for a mission to detect Earth-sized planets in the extended solar neighborhood</title>

Abstract

The thirty or so extrasolar planets that have been discovered to date are all about as large as Jupiter or larger. Finding Earthsize planets is a substantially more difficult task. We propose the use of spacebased differential photometry to detect the periodic changes in brightness of several hours duration caused by planets transiting their parent stars. The change in brightness for a Sun-Earth analog transit is 8x105. We describe the instrument and mission concepts that will monitor 100,000 main-sequence stars and detect on the order of 500 Earth-size planets, if terrestrial planets are common in the extended solar neighborhood.We have performed and will discuss end-to-end laboratory measurements that demonstrate the feasibility of differential photometry under realistic operating conditions. The tests included a realistic star field in which individual transits can be generated, fast optics with a realistic point spread function, and a flight-type back-illuminated CCD. Spacecraft motion was simulated using piezoelectric transducers. Data acquisition and processing used the same methods as planned for the space mission. A system-level differential-photometric precision of 1 O has been demonstrated under realistic conditions.

TheKepler Missionand Eclipsing Binaries

“…The mission has been described in a number of papers (Borucki et al 2005, Koch et al 2004. The basic photometric capability and mission design have remained nearly the same since selection by NASA in December 2001 as the tenth Discovery mission.…”

“…With regard to the distance, we are expecting that this can be derived from astrometric parallaxes out to 1 kpc using the Kepler data. Based upon laboratory measurements (Koch, et al 2000), simulations and the high SNR of the data, this does appear to be plausible. The GAIA mission (Niarchos, Munari and Zwitter 2006) results will also be very useful in refining and confirming some of these cases.…”

AutoBayes: a system for generating data analysis programs from statistical models

“…We are currently testing AutoBayes in two larger case studies concerning data analysis tasks for finding extra-solar planets, either by measuring dips in the luminosity of stars (Koch et al, 2000), or by measuring Doppler effects (Marcy & Butler, 1997), respectively. Both projects required substantial effort to manually set up data analysis programs.…”

Finding Earth-size planets in the habitable zone: theKepler Mission

“…The Kepler Technology Demonstration (Koch, et al 2000) was used once again in 2007 to test a single string engineering model of the flight detector system design. These tests demonstrated that the instrument noise requirement was met (after making modifications The convolved also includes a 3-4.5% loss for contamination.…”

“…However, the transit method proposed by Borucki and Summers (1984) can detect Earth-size planets in the HZ. Thus, it was necessary to show that: 1) the variability of the Sun and presumably most stars similar to 18 W. Borucki et al the Sun on the time scale of a transit (on the order of 10-12 hours) is substantially smaller in amplitude than that of a Sun-Earth transit analog (84 ppm) (Jenkins 2002) and 2) to demonstrate that a space-based photometer with all the known forms of realistic noise has a combined differential photometric precision 20 ppm, one-sigma on the time scale of a transit (Koch, et al 2000). The concept was proposed as a Discovery mission four times before finally being selected in December 2001 as NASA's tenth Discovery mission.…”