Stellar proper motion and the timing of planetary transits

Abstract

Duration and period of transits in extrasolar planetary systems can exhibit long-term variations for a variety of reasons. Here we investigate how systemic proper motion, which steadily re-orients planetary orbit with respect to our line of sight, affects the timing of transits. We find that in a typical system with a period of several days proper motion at the level of 100 mas/yr makes transit duration vary at a rate ~10-100 ms/yr. In some isolated systems this variation is at the measurable level (can be as high as 0.6 s/yr for GJ436) and may exceed all other transit timing contributions (due to the general relativity, stellar quadrupole, etc.). In addition, proper motion causes evolution of the observed orbital period via the Shklovskii effect at a rate $\gtrsim 10$ $\mu$s/yr for the nearby transiting systems (0.26 ms/yr in GJ436), which in some cases exceeds all other contributions to $\dot{P}$. Earth's motion around the Sun gives rise to additional periodic timing signal (even for systems with zero intrinsic proper motion) allowing a full determination of the spatial orientation of the planetary orbit. Unlike most other timing effects the proper motion signatures persist even in systems with zero eccentricity and get stronger as the planetary period increases. They should be the dominant cause of transit timing variations in isolated wide separation (periods of months) systems that will be sought by Kepler.

7 pages, 2 tables, submitted to ApJ

References in corpus (19)

• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• Orbital perturbations on transiting planets: A possible method to measure stellar quadrupoles and to detect Earth-mass planets
• Using Stellar Limb-Darkening to Refine the Properties of HD 209458b
• Measurement of the Spin-Orbit Alignment in the Exoplanetary System HD 189733
• Tidal Evolution Of the Planetary System around HD 83443
• Using long-term transit timing to detect terrestrial planets
• Characterizing the Orbital Eccentricities of Transiting Extrasolar Planets with Photometric Observations
• Observability of the General Relativistic Precession of Periastra in Exoplanets
• A ~5 M_earth Super-Earth Orbiting GJ 436?: The Power of Near-Grazing Transits
• A Photometric Diagnostic to Aid in the Identification of Transiting Extra-Solar Planets
• A Possible Spin-Orbit Misalignment in the Transiting Eccentric Planet HD 17156b
• Measurement of the Spin-Orbit Angle of Exoplanet HAT-P-1b
• Periastron Precession Measurements in Transiting Extrasolar Planetary Systems at the Level of General Relativity
• SPIN-ORBIT INTERACTION IN NEUTRON STAR/MAIN SEQUENCE BINARIES AND IMPLICATIONS FOR PULSAR TIMING
• The Spin-Orbit Alignment of the HD17156 Transiting Eccentric Planetary System
• The Parkes Pulsar Timing Array
• Exoplanet Transit Parallax
• Post-Newtonian Theory for Precision Doppler Measurements of Binary Star Orbits
• Closure Phase Signatures of Planet Transit Events

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