Kepler Mission Design, Realized Photometric Performance, and Early Science (1001.0268v2)

Abstract: The Kepler Mission, launched on Mar 6, 2009 was designed with the explicit capability to detect Earth-size planets in the habitable zone of solar-like stars using the transit photometry method. Results from just forty-three days of data along with ground-based follow-up observations have identified five new transiting planets with measurements of their masses, radii, and orbital periods. Many aspects of stellar astrophysics also benefit from the unique, precise, extended and nearly continuous data set for a large number and variety of stars. Early results for classical variables and eclipsing stars show great promise. To fully understand the methodology, processes and eventually the results from the mission, we present the underlying rationale that ultimately led to the flight and ground system designs used to achieve the exquisite photometric performance. As an example of the initial photometric results, we present variability measurements that can be used to distinguish dwarf stars from red giants.

• The paper presents a novel approach to transit photometry design, enabling the detection of Earth-size exoplanets with precisions below 20 ppm.
• It leverages a one-meter Schmidt telescope and continuous observation of over 100,000 stars to ensure consistent and robust data collection.
• Early results include the discovery of five new exoplanets and demonstrate effective filtering of false positives via pixel-level analysis.

Overview of the Kepler Mission Design, Realized Photometric Performance, and Early Science

The paper provides a comprehensive investigation of the Kepler Mission, which has the primary aim of detecting Earth-size planets in the habitable zones around solar-like stars, using transit photometry. Launched on March 6, 2009, the mission outlines its objective to measure planetary properties such as mass, radius, and orbital period, with early successes already realized in the detection of five new exoplanets in just 43 days of data collection.

Mission Design and Scientific Goals

The Kepler Mission's design is predicated on several critical scientific requirements, which aimed to maximize its capabilities in detecting Earth-size exoplanets. Three pivotal aspects include:

• Mission Duration: The mission required at least three years to detect at least three transits of Earth-size planets located in the habitable zones, ensuring that observed brightness changes are consistent and periodic.
• Sample Size: Kepler observes upwards of 100,000 solar-like stars, predicting approximately 25 Earth-like planets in its surveyed stars.
• Photometric Precision: Detecting the diminutive transit signal of Earth-size planets around solar analogs demands pristine photometric precision, notably less than 20 ppm over a 6.5-hour observation window.

Instrumentation and Observing Strategy

The Kepler photometer employs a one-meter class Schmidt telescope with a field of view exceeding 100 square degrees. Positioned in an Earth-trailing heliocentric orbit, this setup circumvents terrestrial disturbances such as radiation belts and atmospheric drag, which are critical for maintaining the stability necessary for precision observations. The spacecraft observes a fixed star field, optimizing data continuity and maximizing the potential for prolonged scientific return.

Initial Results and Performance

The paper elaborates on the Kepler Mission’s initial remarkable performance, which includes the discovery of five new exoplanets with determinations of radii, masses, and orbits exemplifying the capabilities of the mission. Noteworthy numerical results, including a photometric precision that remains stellar even among highly saturated stars, underscore the mission's technical successes. The team successfully differentiates dwarf stars from red giants based on variability, utilizing a thorough pixel-level data analysis which aids in filtering false-positive transiting planet signals.

Implications and Future Prospects

The implications of the Kepler mission extend into both exoplanetary science and stellar astrophysics. The availability of continuous, highly precise photometric data represents an unprecedented opportunity for the paper of stellar oscillations, eclipsing binaries, and pulsating stars. It is anticipated that ongoing data collection may significantly enhance our understanding of stellar mass and age relationships, particularly as long-term observation datasets enable more precise astrometric measurements such as parallax.

The expectation is that over time, Kepler will not only catalog a substantial number of exoplanets but also contribute critical insights into the broader field of stellar astrophysics. Future research building on Kepler's observations may refine models of stellar evolution, validate exoplanet discovery techniques, and continue to reduce false-positive rates through enhanced photometric analysis.

In summary, the Kepler Mission exemplifies a highly focused, methodically planned, and technologically robust endeavor that has already achieved significant early scientific return while promising a wealth of future discoveries in both exoplanetary science and related astrophysical fields.