Cunningham, Andrew J., Frank, Adam, Varniere, Peggy, Mitran, Sorin, Jones, Thomas W.
A description is given of the algorithms implemented in the AstroBEAR adaptive mesh refinement code for ideal magnetohydrodynamics. The code provides several high resolution, shock capturing schemes...
Evidence for Growth of Eccentricity and Mass Clearing in a Disc Interior to a Planet (2007)
Edgar, Richard G., Blackman, Eric, Quillen, Alice, Varniere, Peggy, Frank, Adam
We present computational results showing eccentricity growth in the inner portions of a protoplanetary disc. We attribute this to the evolving surface density of the disc. The planet creates a gap,...
Tagger, Michel, Varniere, Peggy
We present a possible explanation for the high-frequency Quasi-Periodic Oscillations of microquasars by an MHD instability that combines the physics developed, in different contexts, for the...
Blackman, Eric G., Penna, Robert F., Varniere, Peggy
By combining data from different published 3-D simulations of Keplerian shearing boxes unstable to the magnetorotational instability (MRI), we highlight tight anti-correlations between the total...
Observational Properties of Proto-planetary Disk Gaps (2005)
Varniere, Peggy, Bjorkman, J. E., Quillen, Adam Frank Alice C., Carciofi, A. C., Whitney, Barbara A., Wood, Kenneth
We study the effects of an annular gap induced by an embedded proto-planet on disk scattered light images and the infrared spectral energy distribution. We find that the outer edge of a gap is...
A simple model for the complex lag structure of microquasars (2005)
The phase lag structure between the hard and soft X-ray photons observed in GRS 1915+105 and XTE J1550+564 has been said to be ``complex'' because the phase of the Quasi-Periodic Oscillation...
On the Planet and the Disk of CoKuTau/4 (2004)
Quillen, Alice C., Blackman, Eric G., Frank, Adam, Varniere, Peggy
Spitzer observations of the young star CoKuTau/4 reveal a disk with a 10 AU hole that is most likely caused by a newly formed planet. Assuming that the planet opened a gap in the viscous disk, we...
Magnetic floods: a scenario for the variability of the microquasar GRS 1915+105 (2004)
Tagger, Michel, Varniere, Peggy, Rodriguez, Jerome, Pellat, Rene
We present a scenario for the variability of the microquasar GRS 1915+105. This starts from previous works, leading to the tentative identification of the Accretion-Ejection Instability as the source...
Driving spiral arms in the circumstellar disks of HD 100546 and HD 141569A (2003)
Quillen, Alice C., Varniere, Peggy, Minchev, Ivan, Frank, Adam
With 2D hydrodynamical simulations of disks perturbed externally by stars, brown dwarfs or planets we investigate possible scenarios that can account for the spiral structure in circumstellar disks....
The Evolution of Protoplanetary Disk Edges (2003)
Varniere, Peggy, Quillen, A. C., Frank, Adam
We investigate gap formation in gaseous protostellar disks by a planet in a circular orbit in the limit of low disk viscosity. This regime may be appropriate to an aging disk after the epoch of...
Accretion-ejection instability in magnetized disks: Feeding the corona with Alfven waves (2002)
Varniere, Peggy, Tagger, Michel
We present a detailed calculation of the mechanism by which the Accretion-Ejection Instability can extract accretion energy and angular momentum from a magnetized disk, and redirect them to its...