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We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity spectroscopic data leads to a planet with R_p = 1.008+-0.071 R_Jup and M_p =0.855+-0.059 M_Jup, orbiting a host star with R_* = 0.946+-0.054 R_sun and M_* = 1.022+-0.101 M_sun. Comparison of the high resolution stellar spectrum with synthetic spectra and stellar evolution models indicates the host star is a near-solar metallicity ([Fe/H]= 0.01+-0.10) solar analog (Teff = 5700+-150 K, log g= 4.5+-0.2) of intermediate age (Tau = 2.3+5.8-2.2 Gyr).
Although the Sun is our closest star by many orders of magnitude and despite having sunspot records stretching back to ancient China, our knowledge of the Suns magnetic field is far from complete. Indeed, even now, after decades of study, the most ob vious manifestations of magnetic fields in the Sun (e.g. sunspots, flares and the corona) are scarcely understood at all. These failures in spite of intense effort suggest that to improve our grasp of magnetic fields in stars and of astrophysical dynamos in general, we must broaden our base of examples beyond the Sun; we must study stars with a variety of ages, masses, rotation rates, and other properties, so we can test models against as broad a range of circumstances as possible. Over the next decade, an array of indirect techniques will be supplemented by rapidly maturing new capabilities such as gyrochronology, asteroseismology and precision photometry from space, which will transform our understanding of the temporal variability of stars and stellar systems. In this White Paper we will outline some of the key science questions in this area along with the techniques that could be used to bring new insights to these questions.
We have performed photometric observations of nearly 7 million stars with 8 < V < 15 with the SuperWASP-North instrument from La Palma between 2004 May-September. Fields in the RA range 17-18hr, yielding over 185,000 stars with sufficient quality dat a, have been searched for transits using a modified box least-squares (BLS) algorithm. We find a total of 58 initial transiting candidates which have high S/N in the BLS, show multiple transit-like dips and have passed visual inspection. Analysis of the blending and inferred planetary radii for these candidates leaves a total of 7 transiting planet candidates which pass all the tests plus 4 which pass the majority. We discuss the derived parameters for these candidates and their properties and comment on the implications for future transit searches.
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