2001/04/30 by B. S. Gaudi, Michael D. Albrow, M. D. Albrow +31
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Brown dwarf #Bulge #Einstein radius #Galaxy #Gamma-ray bursts and supernovae #Gravitational lens #Gravitational microlensing #Light curve #Mass distribution #Mass ratio #Photometry (optics) #Physics #Planet #Planetary mass #Planetary system #RADIUS #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/337987
66 pages, 18 figures, minor changes, primary conclusions unchanged. To appear in February 10 ApJ (v566). Postscript version with high-quality figures available at http://www.sns.ias.edu/~gaudi/publications.html . Data available at http://www.astro.rug.nl/~planet/planetpapers.html
arxiv created 2001/10/11 · openalex publication_date 2002/02/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We analyze 5 years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single-lens light curves that are indicative of the presence of planetary companions to the primary microlenses. Using strict event-selection criteria, we construct a well-defined sample of 43 intensively monitored events. We search for planetary perturbations in these events over a densely sampled region of parameter space spanning two decades in mass ratio and projected separation, but find no viable planetary candidates. By combining the detection efficiencies of the events, we find that, at 95% confidence, less than 25% of our primary lenses have companions with mass ratio q = 10 -2 and separations in the lensing zone, [0.6-1.6]θ E , where θ E is the Einstein ring radius. Using a model of the mass, velocity, and spatial distribution of bulge lenses, we infer that the majority of our lenses are likely M dwarfs in the Galactic bulge. We conclude that less than 33% of M dwarfs in the Galactic bulge have companions with mass m p = M J between 1.5 and 4 AU, and less than 45% have companions with m p = 3 M J between 1 and 7 AU, the first significant limits on planetary companions to M dwarfs. We consider the effects of the finite size of the source stars and changing our detection criterion, but find that these do not alter our conclusions substantially.