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Full-Text Articles in Physical Sciences and Mathematics
Meteorological Conditions At Racetrack Playa, Death Valley National Park: Implications For Rock Production And Transport, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joseph N. Spitale, Jani Radebaugh, Kevin H. Baines
Meteorological Conditions At Racetrack Playa, Death Valley National Park: Implications For Rock Production And Transport, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joseph N. Spitale, Jani Radebaugh, Kevin H. Baines
Brian Jackson
Three decades of weather records at meteorological stations near Death Valley National Park are analyzed in an attempt to gauge the frequency of conditions that might form and erase the famous trails of wind-blown rocks in the mud of Racetrack Playa. Trail formation requires the playa to be wet, followed by strong winds and/or freezing conditions. Weather records are compared with a limited set of meteorological data that were acquired in situ at the playa over three winters and that indicate freezing on 50, 29, and 15 nights during the winters of 2007/08–09/10, respectively, as well as with the hydrological …
Kepler And Ground-Based Transits Of The Exo-Neptune Hat-P-11b, Drake Deming, Pedro V. Sada, Brian Jackson, Steven W. Peterson, Eric Agol, Heather A. Knutson, Donald E. Jennings, Flynn Haase, Kevin Bays
Kepler And Ground-Based Transits Of The Exo-Neptune Hat-P-11b, Drake Deming, Pedro V. Sada, Brian Jackson, Steven W. Peterson, Eric Agol, Heather A. Knutson, Donald E. Jennings, Flynn Haase, Kevin Bays
Brian Jackson
We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields Rp = 4.31 R⊕ ± 0.06 R ⊕ and Rs = 0.683 R☉ ± 0.009 R☉, both about 3σ smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening …
Ice Rafts Not Sails: Floating The Rocks At Racetrack Playa, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joe Spitale, John M. Keller
Ice Rafts Not Sails: Floating The Rocks At Racetrack Playa, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joe Spitale, John M. Keller
Brian Jackson
We suggest that the existence of many of the rock-carved trails at Racetrack Playa in Death Valley National Park is predominantly due to the effect of arbitrarily weak winds on rocks that are floated off the soft bed by small rafts of ice, as also occurs in arctic tidal beaches to form boulder barricades. These ice cakes need not have a particularly large surface area if the ice is adequately thick—the ice cakes allow the rocks to move by buoyantly reducing the reaction and friction forces at the bed, not by increasing the wind drag. The parameter space of ice …