2008/02/19 by E. Miller-Ricci, Eliza Miller‐Ricci, J. F. Rowe +16 · 3 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Exoplanet #Photometry (optics) #Physics #Planet #Planetary system #Spitzer Space Telescope #Stars #Starspot #Stellar, planetary, and galactic studies #Transit (satellite) #astro-ph
paper · pdf · doi:10.1086/587634
26 pages, 7 figures, accepted to ApJ
arxiv created 2008/02/19 · openalex publication_date 2008/07/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We have measured transit times for HD 189733b passing in front of its bright ( V = 7.67), chromospherically active, and spotted parent star. Nearly continuous broadband optical photometry of this system was obtained with the Microvariability and Oscillations of Stars ( MOST ) space telescope during 21 days in 2006 August, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. There are no transit timing variations above the level of ±45 s, ruling out super-Earths (of masses 1-4 M ⊕ ) in the 1:2 and 2:3 inner resonances, and planets of 20 M ⊕ in the 2:1 outer resonance of the known planet. We also discuss complications in measuring transit times for a planet that transits an active star with large starspots, and how the transits can help constrain and test spot models. This has implications for the large number of such systems expected to be discovered by the COROT and Kepler missions.