The planet formation imager

The Planet Formation Imager (PFI, www.planetformationimager.org) is a next-generation infrared interferometer array with the primary goal of imaging the active phases of planet formation in nearby star forming regions. PFI will be sensitive to warm dust emission using mid-infrared capabilities made possible by precise fringe tracking in the near-infrared. An L/M band combiner will be especially sensitive to thermal emission from young exoplanets (and their disks) with a high spectral resolution mode to probe the kinematics of CO and H₂O gas. In this paper, we give an overview of the main science goals of PFI, define a baseline PFI architecture that can achieve those goals, point at remaining technical challenges, and suggest activities today that will help make the Planet Formation Imager facility a reality.     

Propagation of local errors in the solutions of the differential equations for orbital elements

The propagation of errors in the solutions of the differential equations for the orbital elements of perturbed two-body motion is investigated. It is shown that the error in the time-element grows linearly for differential equations for orbital elements when only perturbations are present on the right-hand side, cubically for formulations which have a two-body term on the right-hand side, and linearly for formulations based upon extended phase space Hamiltonians.     

Hello Mars, goodbye Hubble?

Successes at Mars make the promise of more money for space exploration appealing, but will other projects pay the price? Peter Bond reports.     

Analytical satelite theory in extended phase space

In the present note we show how a simple canonical transformation in extended phase space makes the transition from classical Delaunay elements to the Scheifele variables. We do not use spherical coordinates or Hamilton-Jacobi theory. The meaning of the new variables is briefly explained, especially the use of the true anomaly as one of the variables.     

Auroral surges in southern hemisphere

All-sky camera photographs from Mawson have been used to determine the speeds of westward travelling auroral surges over Antarctica. The results indicate surge speeds comparable to the largest recorded for northern hemisphere surges.     

Ups and downs

Cluster goes up but will planetary programmes go down? Peter Bond reports on space mission plans and achievements.