A search for planets transiting the M-dwarf debris disc host, AU Microscopii |
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| Authors: | Leslie Hebb Larry Petro Holland C Ford David R Ardila Ignacio Toledo Dante Minniti David A Golimowski Mark Clampin |
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| Institution: | School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS;Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA;Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA;Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125, USA;Department of Astronomy, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22, Chile;NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771, USA |
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| Abstract: | We present high-cadence, high-precision multiband photometry of the young, M1Ve, debris disc star, AU Microscopii. The data were obtained in three continuum filters spanning a wavelength range from 4500 to 6600 Å, plus Hα, over 28 nights in 2005. The light curves show intrinsic stellar variability due to star-spots with an amplitude in the blue band of 0.051 mag and a period of 4.847 d. In addition, three large flares were detected in the data which all occur near the minimum brightness of the star. We remove the intrinsic stellar variability and combine the light curves of all the filters in order to search for transits by possible planetary companions orbiting in the plane of the nearly edge-on debris disc. The combined final light curve has a sampling of 0.35 min and a standard deviation of 6.8 mmag. We performed Monte Carlo simulations by adding fake transits to the observed light curve and find with 95 per cent significance that there are no Jupiter mass planets orbiting in the plane of the debris disc on circular orbits with periods, P ≤ 5 d. In addition, there are no young Neptune like planets (with radii 2.5 times smaller than the young Jupiter) on circular orbits with periods, P ≤ 3 d. |
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| Keywords: | circumstellar matter stars: individual: AU Mic stars: late-type planetary systems stars: pre-main-sequence |
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